Tag: extreme weather events

bookmark_borderBuyer Beware: Flood and Storm Damage

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As sea levels rise and storms become more volatile, some areas are actually reducing their standards for building codes.

The Insurance Institute for Business & Home Safety released their 2018 report. The analysis assesses the progress of 18 hurricane-prone coastal states along the Gulf of Mexico and the Atlantic Coast in strengthening their residential building codes.

“While many states have affirmed their commitment to strong building codes, in others there is a concerning lack of progress in the adoption and enforcement of updated residential building code systems. Because residential building codes represent a minimum life-safety standard for occupancy, the findings suggest that many homes remain at risk from severe hurricane events.”

Below are the 2018 state scores, based on a 100-point scale, where 100 is the best available score:

Hurricane Ratings
Hurricane Ratings

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bookmark_borderClimate Science Special Report: Human Induced

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The Fourth National Climate Assessment (NCA4), Volume I has determined that climate change is being unduly accelerated by human activities.

The report is an authoritative assessment of the science of climate change, with a focus on the United States. It represents the first of two volumes of the Fourth National Climate Assessment, mandated by the Global Change Research Act of 1990.

The report’s summary states:

Global annually averaged surface air temperature has increased by about 1.8°F (1.0°C) over the last 115 years (1901–2016). This period is now the warmest in the history of modern civilization. The last few years have also seen record-breaking, climate-related weather extremes, and the last three years have been the warmest years on record for the globe. These trends are expected to continue over climate timescales.This assessment concludes, based on extensive evidence, that it is extremely likely that human activities, especially emissions of greenhouse gases, are the dominant cause of the observed warming since the mid-20th century. For the warming over the last century, there is no convincing alternative explanation supported by the extent of the observational evidence.In addition to warming, many other aspects of global climate are changing, primarily in response to human activities. Thousands of studies conducted by researchers around the world have documented changes in surface, atmospheric, and oceanic temperatures; melting glaciers; diminishing snow cover; shrinking sea ice; rising sea levels; ocean acidification; and increasing atmospheric water vapor.

For example, global average sea level has risen by about 7–8 inches since 1900, with almost half (about 3 inches) of that rise occurring since 1993. Human-caused climate change has made a substantial contribution to this rise since 1900, contributing to a rate of rise that is greater than during any preceding century in at least 2,800 years. Global sea level rise has already affected the United States; the incidence of daily tidal flooding is accelerating in more than 25 Atlantic and Gulf Coast cities.

Global average sea levels are expected to continue to rise—by at least several inches in the next 15 years and by 1–4 feet by 2100. A rise of as much as 8 feet by 2100 cannot be ruled out. Sea level rise will be higher than the global average on the East and Gulf Coasts of the United States.

Changes in the characteristics of extreme events are particularly important for human safety, infrastructure, agriculture, water quality and quantity, and natural ecosystems. Heavy rainfall is increasing in intensity and frequency across the United States and globally and is expected to continue to increase. The largest observed changes in the United States have occurred in the Northeast.

Heatwaves have become more frequent in the United States since the 1960s, while extreme cold temperatures and cold waves are less frequent. Recent record-setting hot years are projected to become common in the near future for the United States, as annual average temperatures continue to rise. Annual average temperature over the contiguous United States has increased by 1.8°F (1.0°C) for the period 1901–2016; over the next few decades (2021–2050), annual average temperatures are expected to rise by about 2.5°F for the United States, relative to the recent past (average from 1976–2005), under all plausible future climate scenarios.

The incidence of large forest fires in the western United States and Alaska has increased since the early 1980s and is projected to further increase in those regions as the climate changes, with profound changes to regional ecosystems.

Annual trends toward earlier spring melt and reduced snowpack are already affecting water resources in the western United States and these trends are expected to continue. Under higher scenarios, and assuming no change to current water resources management, chronic, long-duration hydrological drought is increasingly possible before the end of this century.

The magnitude of climate change beyond the next few decades will depend primarily on the amount of greenhouse gases (especially carbon dioxide) emitted globally. Without major reductions in emissions, the increase in annual average global temperature relative to preindustrial times could reach 9°F (5°C) or more by the end of this century. With significant reductions in emissions, the increase in annual average global temperature could be limited to 3.6°F (2°C) or less.

The global atmospheric carbon dioxide (CO2) concentration has now passed 400 parts per million (ppm), a level that last occurred about 3 million years ago, when both global average temperature and sea level were significantly higher than today. Continued growth in CO2 emissions over this century and beyond would lead to an atmospheric concentration not experienced in tens to hundreds of millions of years. There is broad consensus that the further and the faster the Earth system is pushed towards warming, the greater the risk of unanticipated changes and impacts, some of which are potentially large and irreversible.

The observed increase in carbon emissions over the past 15–20 years has been consistent with higher emissions pathways. In 2014 and 2015, emission growth rates slowed as economic growth became less carbon-intensive. Even if this slowing trend continues, however, it is not yet at a rate that would limit global average temperature change to well below 3.6°F (2°C) above preindustrial levels.

Introduction

New observations and new research have increased our understanding of past, current, and future climate change since the Third U.S. National Climate Assessment (NCA3) was published in May 2014. This Climate Science Special Report (CSSR) is designed to capture that new information and build on the existing body of science in order to summarize the current state of knowledge and provide the scientific foundation for the Fourth National Climate Assessment (NCA4).

Since NCA3, stronger evidence has emerged for continuing, rapid, human-caused warming of the global atmosphere and ocean. This report concludes that “it is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century. For the warming over the last century, there is no convincing alternative explanation supported by the extent of the observational evidence.”

The last few years have also seen record-breaking, climate-related weather extremes, the three warmest years on record for the globe, and continued decline in arctic sea ice. These trends are expected to continue in the future over climate (multidecadal) timescales. Significant advances have also been made in our understanding of extreme weather events and how they relate to increasing global temperatures and associated climate changes. Since 1980, the cost of extreme events for the United States has exceeded $1.1 trillion; therefore, better understanding of the frequency and severity of these events in the context of a changing climate is warranted.

Periodically taking stock of the current state of knowledge about climate change and putting new weather extremes, changes in sea ice, increases in ocean temperatures, and ocean acidification into context ensures that rigorous, scientifically-based information is available to inform dialogue and decisions at every level. This climate science report serves as the climate science foundation of the NCA4 and is generally intended for those who have a technical background in climate science. In this Executive Summary, green boxes present highlights of the main report. These are followed by related points and selected figures providing more scientific details. The summary material on each topic presents the most salient points of chapter findings and therefore represents only a subset of the report’s content. For more details, the reader is referred to the individual chapters. This report discusses climate trends and findings at several scales: global, nationwide for the United States, and for ten specific U.S. regions (shown in Figure 1 in the Guide to the Report). A statement of scientific confidence also follows each point in the Executive Summary. The confidence scale is described in the Guide to the Report. At the end of the Executive Summary and in Chapter 1: Our Globally Changing Climate, there is also a summary box highlighting the most notable advances and topics since NCA3 and since the 2013 Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report.

Global and U.S. Temperatures Continue to Rise

Long-term temperature observations are among the most consistent and widespread evidence of a warming planet. Temperature (and, above all, its local averages and extremes) affects agricultural productivity, energy use, human health, water resources, infrastructure, natural ecosystems, and many other essential aspects of society and the natural environment. Recent data add to the weight of evidence for rapid global-scale warming, the dominance of human causes, and the expected continuation of increasing temperatures, including more record-setting extremes. (Ch. 1)

Changes in Observed and Projected Global Temperature

  • Global annual average temperature (as calculated from instrumental records over both land and oceans) has increased by more than 1.2°F (0.65°C) for the period 1986–2016 relative to 1901–1960; the linear regression change over the entire period from 1901–2016 is 1.8°F (1.0°C) (very high confidence; Fig. ES.1). Longer-term climate records over past centuries and millennia indicate that average temperatures in recent decades over much of the world have been much higher, and have risen faster during this time period than at any time in the past 1,700 years or more, the time period for which the global distribution of surface temperatures can be reconstructed (high confidence). (Ch. 1)

Figure 1

(left) Global annual average temperature has increased by more than 1.2°F (0.7°C) for the period 1986–2016 relative to 1901–1960. Red bars show temperatures that were above the 1901–1960 average, and blue bars indicate temperatures below the average. (right) Surface temperature change (in °F) for the period 1986–2016 relative to 1901–1960. Gray indicates missing data. From Figures 1.2. and 1.3 in Chapter 1.

  • Many lines of evidence demonstrate that it is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century. Over the last century, there are no convincing alternative explanations supported by the extent of the observational evidence. Solar output changes and internal natural variability can only contribute marginally to the observed changes in climate over the last century, and there is no convincing evidence for natural cycles in the observational record that could explain the observed changes in climate. (Very high confidence) (Ch. 1)

    Figure 2

    The likely range of the human contribution to the global mean temperature increase over the period 1951–2010 is 1.1° to 1.4°F (0.6° to 0.8°C), and the central estimate of the observed warming of 1.2°F (0.65°C) lies within this range (high confidence). This translates to a likely human contribution of 92%–123% of the observed 1951–2010 change. The likely contributions of natural forcing and internal variability to global temperature change over that period are minor (high confidence). (Ch. 3; Fig. ES.2)

  • Natural variability, including El Niño events and other recurring patterns of ocean–atmosphere interactions, impact temperature and precipitation, especially regionally, over timescales of months to years. The global influence of natural variability, however, is limited to a small fraction of observed climate trends over decades. (Very high confidence) (Ch. 1)
  • Global climate is projected to continue to change over this century and beyond. The magnitude of climate change beyond the next few decades will depend primarily on the amount of greenhouse (heat-trapping) gases emitted globally and on the remaining uncertainty in the sensitivity of Earth’s climate to those emissions (very high confidence). With significant reductions in the emissions of greenhouse gases, the global annually averaged temperature rise could be limited to 3.6°F (2°C) or less. Without major reductions in these emissions, the increase in annual average global temperatures relative to pre-industrial times could reach 9°F (5°C) or more by the end of this century. (Ch.1; Fig ES.3)
  • If greenhouse gas concentrations were stabilized at their current level, existing concentrations would commit the world to at least an additional 1.1°F (0.6°C) of warming over this century relative to the last few decades (high confidence in continued warming, medium confidence in amount of warming. (Ch.4)

Figure 3

The two panels above show annual historical and a range of plausible future carbon emissions in units of gigatons of carbon (GtC) per year (left) and the historical observed and future temperature change that would result for a range of future scenarios relative to the 1901–1960 average, based on the central estimate (lines) and a range (shaded areas, two standard deviations) as simulated by the full suite of CMIP5 global climate models (right). By 2081–2100, the projected range in global mean temperature change is 1.1°–4.3°F under the even lower scenario (RCP2.6; 0.6°–2.4°C, green), 2.4°–5.9°F under the lower scenario (RCP4.5; 1.3°–3.3°C, blue), 3.0°–6.8°F under the mid-high scenario (RCP6.0; 1.6°–3.8°C, not shown) and 5.0°–10.2°F under the higher scenario (RCP8.5; 2.8°–5.7°C, orange). See the main report for more details on these scenarios and implications. Based on Figure 4.1 in Chapter 4.

Changes in Observed and Projected U.S. Temperature

  • Annual average temperature over the contiguous United States has increased by 1.2°F (0.7°C) for the period 1986–2016 relative to 1901–1960 and by 1.8°F (1.0°C) based on a linear regression for the period 1901–2016 (very high confidence). Surface and satellite data are consistent in their depiction of rapid warming since 1979 (high confidence). Paleo-temperature evidence shows that recent decades are the warmest of the past 1,500 years (medium confidence). (Ch. 6)
  • Annual average temperature over the contiguous United States is projected to rise (very high confidence). Increases of about 2.5°F (1.4°C) are projected for the period 2021–2050 relative to the average from 1976–2005 in all RCP scenarios, implying recent record-setting years may be “common” in the next few decades (high confidence). Much larger rises are projected by late century (2071–2100): 2.8°–7.3°F (1.6°–4.1°C) in a lower scenario (RCP4.5) and 5.8°–11.9°F (3.2°–6.6°C) in a higher scenario (RCP8.5) (high confidence). (Ch. 6; Fig. ES.4)
  • In the United States, the urban heat island effect results in daytime temperatures 0.9°–7.2°F (0.5°–4.0°C) higher and nighttime temperatures 1.8°– 4.5°F (1.0°–2.5°C) higher in urban areas than in rural areas, with larger temperature differences in humid regions (primarily in the eastern United States) and in cities with larger and denser populations. The urban heat island effect will strengthen in the future as the structure and spatial extent as well as population density of urban areas change and grow (high confidence). (Ch. 10)

Figure 4

These maps show the projected changes in annual average temperatures for mid- and late-21st century for two future pathways. Changes are the differences between the average projected temperatures for mid-century (2036–2065; top), and late-century (2070-2099; bottom), and those observed for the near-present (1976–2005). See Figure 6.7 in Chapter 6 for more details.

Many Temperature and Precipitation Extremes Are Becoming More Common

Temperature and precipitation extremes can affect water quality and availability, agricultural productivity, human health, vital infrastructure, iconic ecosystems and species, and the likelihood of disasters. Some extremes have already become more frequent, intense, or of longer duration, and many extremes are expected to continue to increase or worsen, presenting substantial challenges for built, agricultural, and natural systems. Some storm types such as hurricanes, tornadoes, and winter storms are also exhibiting changes that have been linked to climate change, although the current state of the science does not yet permit detailed understanding.

Observed Changes in Extremes

Figure 5

The frequency of cold waves has decreased since the early 1900s, and the frequency of heat waves has increased since the mid-1960s (the Dust Bowl era of the 1930s remains the peak period for extreme heat in the United States). (Very high confidence). (Ch. 6)

  • The frequency and intensity of extreme heat and heavy precipitation events are increasing in most continental regions of the world (very high confidence). These trends are consistent with expected physical responses to a warming climate. Climate model studies are also consistent with these trends, although models tend to underestimate the observed trends, especially for the increase in extreme precipitation events (very high confidence for temperature, high confidence for extreme precipitation). (Ch. 1)

Figure 6


These maps show the percentage change in several metrics of extreme precipitation by NCA4 region, including (upper left) the maximum daily precipitation in consecutive 5-year periods; (upper right) the amount of precipitation falling in daily events that exceed the 99th percentile of all non-zero precipitation days (top 1% of all daily precipitation events); (lower left) the number of 2-day events with a precipitation total exceeding the largest 2-day amount that is expected to occur, on average, only once every 5 years, as calculated over 1901–2016; and (lower right) the number of 2-day events with a precipitation total exceeding the largest 2-day amount that is expected to occur, on average, only once every 5 years, as calculated over 1958–2016. The number in each black circle is the percent change over the entire period, either 1901–2016 or 1958–2016. Note that Alaska and Hawai‘i are not included in the 1901–2016 maps owing to a lack of observations in the earlier part of the 20th century. (Figure source: CICS-NC / NOAA NCEI). Based on Figure 7.4 in Chapter 7.

  • Recent droughts and associated heat waves have reached record intensity in some regions of the United States; however, by geographical scale and duration, the Dust Bowl era of the 1930s remains the benchmark drought and extreme heat event in the historical record. (Very high confidence) (Ch. 8)
  • Northern Hemisphere spring snow cover extent, North America maximum snow depth, snow water equivalent in the western United States, and extreme snowfall years in the southern and western United States have all declined, while extreme snowfall years in parts of the northern United States have increased. (Medium confidence). (Ch. 7)
  • There has been a trend toward earlier snowmelt and a decrease in snowstorm frequency on the southern margins of climatologically snowy areas (medium confidence). Winter storm tracks have shifted northward since 1950 over the Northern Hemisphere (medium confidence). Potential linkages between the frequency and intensity of severe winter storms in the United States and accelerated warming in the Arctic have been postulated, but they are complex, and, to some extent, contested, and confidence in the connection is currently low. (Ch. 9)
  • Tornado activity in the United States has become more variable, particularly over the 2000s, with a decrease in the number of days per year with tornadoes and an increase in the number of tornadoes on these days (medium confidence). Confidence in past trends for hail and severe thunderstorm winds, however, is low (Ch. 9)

Projected Changes in Extremes

  • The frequency and intensity of extreme high temperature events are virtually certain to increase in the future as global temperature increases (high confidence). Extreme precipitation events will very likely continue to increase in frequency and intensity throughout most of the world (high confidence). Observed and projected trends for some other types of extreme events, such as floods, droughts, and severe storms, have more variable regional characteristics. (Ch. 1)
  • Both extremely cold days and extremely warm days are expected to become warmer. Cold waves are predicted to become less intense while heat waves will become more intense. The number of days below freezing is projected to decline while the number above 90°F will rise. (Very high confidence) (Ch. 6)
  • The frequency and intensity of heavy precipitation events in the United States are projected to continue to increase over the 21st century (high confidence). There are, however, important regional and seasonal differences in projected changes in total precipitation: the northern United States, including Alaska, is projected to receive more precipitation in the winter and spring, and parts of the southwestern United States are projected to receive less precipitation in the winter and spring (medium confidence). (Ch. 7)
  • The frequency and severity of landfalling “atmospheric rivers” on the U.S. West Coast (narrow streams of moisture that account for 30%–40% of the typical snowpack and annual precipitation in the region and are associated with severe flooding events) will increase as a result of increasing evaporation and resulting higher atmospheric water vapor that occurs with increasing temperature. (Medium confidence) (Ch. 9)
  • Projections indicate large declines in snowpack in the western United States and shifts to more precipitation falling as rain than snow in the cold season in many parts of the central and eastern United States (high confidence). (Ch. 7)
  • Substantial reductions in western U.S. winter and spring snowpack are projected as the climate warms. Earlier spring melt and reduced snow water equivalent have been formally attributed to human-induced warming (high confidence) and will very likely be exacerbated as the climate continues to warm (very high confidence). Under higher scenarios, and assuming no change to current water resources management, chronic, long-duration hydrological drought is increasingly possible by the end of this century (very high confidence). (Ch. 8)
  • The human effect on recent major U.S. droughts is complicated. Little evidence is found for a human influence on observed precipitation deficits, but much evidence is found for a human influence on surface soil moisture deficits due to increased evapotranspiration caused by higher temperatures. (High confidence) (Ch. 8)
  • The incidence of large forest fires in the western United States and Alaska has increased since the early 1980s (high confidence) and is projected to further increase in those regions as the climate warms, with profound changes to certain ecosystems (medium confidence). (Ch. 8)
  • Both physics and numerical modeling simulations generally indicate an increase in tropical cyclone intensity in a warmer world, and the models generally show an increase in the number of very intense tropical cyclones. For Atlantic and eastern North Pacific hurricanes and western North Pacific typhoons, increases are projected in precipitation rates (high confidence) and intensity (medium confidence). The frequency of the most intense of these storms is projected to increase in the Atlantic and western North Pacific (low confidence) and in the eastern North Pacific (medium confidence). (Ch. 9)

Oceans Are Rising, Warming, and Becoming More Acidic

Oceans occupy two-thirds of the planet’s surface and host unique ecosystems and species, including those important for global commercial and subsistence fishing. Understanding climate impacts on the ocean and the ocean’s feedbacks to the climate system is critical for a comprehensive understanding of current and future changes in climate.

Global Ocean Heat

  • Ocean heat content has increased at all depths since the 1960s and surface waters have warmed by about 1.3° ± 0.1°F (0.7° ± 0.08°C) per century globally since 1900 to 2016. Under higher scenarios, a global increase in average sea surface temperature of 4.9° ± 1.3°F (2.7° ± 0.7°C) is projected by 2100. (Very high confidence). (Ch. 13)

Global and Regional Sea Level Rise

  • Human-caused climate change has made a substantial contribution to GMSL rise since 1900 (high confidence), contributing to a rate of rise that is greater than during any preceding century in at least 2,800 years (medium confidence). (Ch. 12; Fig. ES.8)
  • Relative to the year 2000, GMSL is very likely to rise by 0.3–0.6 feet (9–18 cm) by 2030, 0.5–1.2 feet (15–38 cm) by 2050, and 1.0–4.3 feet (30–130 cm) by 2100 (very high confidence in lower bounds; medium confidence in upper bounds for 2030 and 2050; low confidence in upper bounds for 2100). Future emissions pathways have little effect on projected GMSL rise in the first half of the century, but significantly affect projections for the second half of the century (high confidence). (Ch. 12)

Figure 8

The top panel shows observed and reconstructed mean sea level for the last 2,500 years. The bottom panel shows projected mean sea level for six future scenarios. The six scenarios—spanning a range designed to inform a variety of decision makers—extend from a low scenario, consistent with continuation of the rate of sea level rise over the last quarter century, to an extreme scenario, assuming rapid mass loss from the Antarctic ice sheet. Note that the range on the vertical axis in the bottom graph is approximately ten times greater than in the top graph. Based on Figure 12.2 and 12.4 in Chapter 12. See the main report for more details.

  • Emerging science regarding Antarctic ice sheet stability suggests that, for higher scenarios, a GMSL rise exceeding 8 feet (2.4 m) by 2100 is physically possible, although the probability of such an extreme outcome cannot currently be assessed. Regardless of emission pathway, it is extremely likely that GMSL rise will continue beyond 2100 (high confidence). (Ch. 12)
  • Relative sea level rise in this century will vary along U.S. coastlines due, in part, to changes in Earth’s gravitational field and rotation from melting of land ice, changes in ocean circulation, and vertical land motion (very high confidence). For almost all future GMSL rise scenarios, relative sea level rise is likely to be greater than the global average in the U.S. Northeast and the western Gulf of Mexico. In intermediate and low GMSL rise scenarios, relative sea level rise is likely to be less than the global average in much of the Pacific Northwest and Alaska. For high GMSL rise scenarios, relative sea level rise is likely to be higher than the global average along all U.S. coastlines outside Alaska. Almost all U.S. coastlines experience more than global mean sea level rise in response to Antarctic ice loss, and thus would be particularly affected under extreme GMSL rise scenarios involving substantial Antarctic mass loss (high confidence). (Ch. 12)

Coastal Flooding

Figure 9

As sea levels have risen, the number of tidal floods each year that cause minor impacts (also called “nuisance floods”) have increased 5- to 10-fold since the 1960s in several U.S. coastal cities (very high confidence). Rates of increase are accelerating in over 25 Atlantic and Gulf Coast cities (very high confidence). Tidal flooding will continue increasing in depth, frequency, and extent this century (very high confidence). (Ch. 12)

  • Assuming storm characteristics do not change, sea level rise will increase the frequency and extent of extreme flooding associated with coastal storms, such as hurricanes and nor’easters (very high confidence). A projected increase in the intensity of hurricanes in the North Atlantic (medium confidence) could increase the probability of extreme flooding along most of the U.S. Atlantic and Gulf Coast states beyond what would be projected based solely on relative sea level rise. However, there is low confidence in the projected increase in frequency of intense Atlantic hurricanes, and the associated flood risk amplification, and flood effects could be offset or amplified by such factors, such as changes in overall storm frequency or tracks. (Ch.12; Fig. ES. 9)

Global Ocean Circulation

  • The potential slowing of the Atlantic meridional overturning circulation (AMOC; of which the Gulf Stream is one component)—as a result of increasing ocean heat content and freshwater-driven buoyancy changes—could have dramatic climate feedbacks as the ocean absorbs less heat and CO2 from the atmosphere. This slowing would also affect the climates of North America and Europe. Any slowing documented to date cannot be directly tied to human-caused forcing, primarily due to lack of adequate observational data and to challenges in modeling ocean circulation changes. Under a higher scenario (RCP8.5), models show that the AMOC weakens over the 21st century (low confidence). (Ch. 13)

Global and Regional Ocean Acidification

  • Higher-latitude systems typically have a lower buffering capacity against changing acidity, exhibiting seasonally corrosive conditions sooner than low-latitude systems. The rate of acidification is unparalleled in at least the past 66 million years (medium confidence). Under the higher scenario (RCP8.5), the global average surface ocean acidity is projected to increase by 100% to 150% (high confidence). (Ch. 13)
  • Acidification is regionally greater than the global average along U.S. coastal systems as a result of upwelling (e.g., in the Pacific Northwest) (high confidence), changes in freshwater inputs (e.g., in the Gulf of Maine) (medium confidence), and nutrient input (e.g., in urbanized estuaries) (high confidence). (Ch. 13)

Ocean Oxygen

  • Increasing sea surface temperatures, rising sea levels, and changing patterns of precipitation, winds, nutrients, and ocean circulation are contributing to overall declining oxygen concentrations at intermediate depths in various ocean locations and in many coastal areas. Over the last half century, major oxygen losses have occurred in inland seas, estuaries, and in the coastal and open ocean (high confidence). Ocean oxygen levels are projected to decrease by as much as 3.5% under the higher scenario (RCP8.5) by 2100 relative to preindustrial values (high confidence). (Ch. 13)

Climate Change in Alaska and across the Arctic Continues to Outpace Global Climate Change

Residents of Alaska are on the front lines of climate change. Crumbling buildings, roads, and bridges and eroding shorelines are commonplace. Accelerated melting of multiyear sea ice cover, mass loss from the Greenland Ice Sheet, reduced snow cover, and permafrost thawing are stark examples of the rapid changes occurring in the Arctic. Furthermore, because elements of the climate system are interconnected (see Box ES.1), changes in the Arctic influence climate conditions outside the Arctic.

Arctic Temperature Increases

  • Rising Alaskan permafrost temperatures are causing permafrost to thaw and become more discontinuous; this process releases additional carbon dioxide and methane resulting in additional warming (high confidence). The overall magnitude of the permafrost-carbon feedback is uncertain (Ch. 2); however, it is clear that these emissions have the potential to compromise the ability to limit global temperature increases. (Ch. 11)
  • Atmospheric circulation patterns connect the climates of the Arctic and the contiguous United States. Evidenced by recent record warm temperatures in the Arctic and emerging science, the midlatitude circulation has influenced observed arctic temperatures and sea ice (high confidence). However, confidence is low regarding whether or by what mechanisms observed arctic warming may have influenced the midlatitude circulation and weather patterns over the continental United States. The influence of arctic changes on U.S. weather over the coming decades remains an open question with the potential for significant impact. (Ch. 11)

Arctic Land Ice Loss

  • Arctic land ice loss observed in the last three decades continues, in some cases accelerating (very high confidence). It is virtually certain that Alaska glaciers have lost mass over the last 50 years, with each year since 1984 showing an annual average ice mass less than the previous year. Over the satellite record, average ice mass loss from Greenland was −269 Gt per year between April 2002 and April 2016, accelerating in recent years (high confidence). (Ch. 11)

Arctic Sea Ice Loss

  • Arctic sea ice loss is expected to continue through the 21st century, very likely resulting in nearly sea ice-free late summers by the 2040s (very high confidence). (Ch. 11)
  • It is very likely that human activities have contributed to observed arctic surface temperature warming, sea ice loss, glacier mass loss, and northern hemisphere snow extent decline (high confidence). (Ch. 11)

Figure 10

September sea ice extent and age shown for (top) 1984 and (middle) 2016, illustrating significant reductions in sea ice extent and age (thickness). The bar graph in the lower right of each panel illustrates the sea ice area (unit: million km2) covered within each age category (> 1 year), and the green bars represent the maximum extent for each age range during the record. The year 1984 is representative of September sea ice characteristics during the 1980s. The years 1984 and 2016 are selected as endpoints in the time series; a movie of the complete time series is available at http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=4489. (bottom) The satellite-era arctic sea ice areal extent trend from 1979 to 2016 for September (unit: million mi2). From Figure 11.1 in Chapter 11.

Limiting Globally Averaged Warming to 2°C (3.6°F) Will Require Major Reductions in Emissions

Human activities are now the dominant cause of the observed trends in climate. For that reason, future climate projections are based on scenarios of how human activities will continue to affect the climate over the remainder of this century and beyond (see Sidebar: Scenarios Used in this Assessment). There remains significant uncertainty about future emissions due to changing economic, political, and demographic factors. For that reason, this report quantifies possible climate changes for a broad set of plausible future scenarios through the end of the century. (Ch. 2, 4, 10, 14)

  • Global mean atmospheric carbon dioxide (CO2) concentration has now passed 400 ppm, a level that last occurred about 3 million years ago, when global average temperature and sea level were significantly higher than today (high confidence). Continued growth in CO2 emissions over this century and beyond would lead to an atmospheric concentration not experienced in tens of millions of years (medium confidence). The present-day emissions rate of nearly 10 GtC per year suggests that there is no climate analog for this century any time in at least the last 50 million years (medium confidence). (Ch. 4)
  • Warming and associated climate effects from CO2 emissions persist for decades to millennia. In the near-term, changes in climate are determined by past and present greenhouse gas emissions modified by natural variability. Reducing net emissions of CO2 is necessary to limit near-term climate change and long-term warming. Other greenhouse gases (e.g., methane) and black carbon aerosols exert stronger warming effects than CO2 on a per ton basis, but they do not persist as long in the atmosphere (Ch. 2); therefore, mitigation of non-CO2 species contributes substantially to near-term cooling benefits but cannot be relied upon for ultimate stabilization goals. (Very high confidence) (Ch. 14)
  • Stabilizing global mean temperature to less than 3.6°F (2°C) above preindustrial levels requires substantial reductions in net global CO2 emissions prior to 2040 relative to present-day values before 2040 and likely requires net emissions to become zero or possibly negative later in the century. After accounting for the temperature effects of non-CO2 species, cumulative global CO2 emissions must stay below about 800 GtC in order to provide a two-thirds likelihood of preventing 3.6°F (2°C) of warming. Given estimated cumulative emissions since 1870, no more than approximately 230 GtC may be emitted in the future in order to remain under this temperature limit. Assuming global emissions are equal to or greater than those consistent with the RCP4.5 scenario, this cumulative carbon threshold would be exceeded in approximately two decades. (Ch. 14)
  • Achieving global greenhouse gas emissions reductions before 2030 consistent with targets and actions announced by governments in the lead up to the 2015 Paris climate conference would hold open the possibility of meeting the long-term temperature goal of limiting global warming to 3.6°F (2°C) above preindustrial levels, whereas there would be virtually no chance if net global emissions followed a pathway well above those implied by country announcements. Actions in the announcements are, by themselves, insufficient to meet a 3.6°F (2°C) goal; the likelihood of achieving that depends strongly on the magnitude of global emissions reductions after 2030. (High confidence) (Ch. 14)
  • Climate intervention or geoengineering strategies such as solar radiation management are measures that attempt to limit or reduce global temperature increases. Further assessments of the technical feasibilities, costs, risks, co-benefits, and governance challenges of climate intervention or geoengineering strategies, which are as yet unproven at scale, are a necessary step before judgments about the benefits and risks of these approaches can be made with high confidence. (High confidence) (Ch. 14)
  • In recent decades, land-use and land-cover changes have turned the terrestrial biosphere (soil and plants) into a net “sink” for carbon (drawing down carbon from the atmosphere), and this sink has steadily increased since 1980 (high confidence). Because of the uncertainty in the trajectory of land cover, the possibility of the land becoming a net carbon source cannot be excluded (very high confidence). (Ch. 10)

There is a Significant Possibility for Unanticipated Changes

Humanity’s effect on the Earth system, through the large-scale combustion of fossil fuels and widespread deforestation and the resulting release of carbon dioxide (CO2) into the atmosphere, as well as through emissions of other greenhouse gases and radiatively active substances from human activities, is unprecedented. There is significant potential for humanity’s effect on the planet to result in unanticipated surprises and a broad consensus that the further and faster the Earth system is pushed towards warming, the greater the risk of such surprises.

There are at least two types of potential surprises: compound events, where multiple extreme climate events occur simultaneously or sequentially (creating greater overall impact), and critical threshold or tipping point events, where some threshold is crossed in the climate system (that leads to large impacts). The probability of such surprises—some of which may be abrupt and/or irreversible—as well as other more predictable but difficult-to-manage impacts, increases as the influence of human activities on the climate system increases. (Ch. 15)

  • Positive feedbacks (self-reinforcing cycles) within the climate system have the potential to accelerate human-induced climate change and even shift the Earth’s climate system, in part or in whole, into new states that are very different from those experienced in the recent past (for example, ones with greatly diminished ice sheets or different large-scale patterns of atmosphere or ocean circulation). Some feedbacks and potential state shifts can be modeled and quantified; others can be modeled or identified but not quantified; and some are probably still unknown. (Very high confidence in the potential for state shifts and in the incompleteness of knowledge about feedbacks and potential state shifts). (Ch. 15)
  • The physical and socioeconomic impacts of compound extreme events (such as simultaneous heat and drought, wildfires associated with hot and dry conditions, or flooding associated with high precipitation on top of snow or waterlogged ground) can be greater than the sum of the parts (very high confidence). Few analyses consider the spatial or temporal correlation between extreme events. (Ch. 15)
  • While climate models incorporate important climate processes that can be well quantified, they do not include all of the processes that can contribute to feedbacks (Ch. 2), compound extreme events, and abrupt and/or irreversible changes. For this reason, future changes outside the range projected by climate models cannot be ruled out (very high confidence). Moreover, the systematic tendency of climate models to underestimate temperature change during warm paleoclimates suggests that climate models are more likely to underestimate than to overestimate the amount of long-term future change (medium confidence). (Ch. 15)

bookmark_borderClimate Disasters Made for Costliest Year

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The National Oceanic and Atmospheric Administration (NOAA) reports:
2017 will be remembered as a year of extremes for the U.S. as floods, tornadoes, hurricanes, drought, fires and freezes claimed hundreds of lives and visited economic hardship upon the nation. Recovery from the ravages of three major Atlantic hurricanes making landfall in the U.S. and an extreme and ongoing wildfire season in the West is expected to continue well into the new year

Billion-dollar disasters in 2017

Last year, the U.S. experienced 16 weather and climate disasters each with losses exceeding $1 billion, totaling approximately $306 billion — a new U.S. record.

Far more tragic was the human toll. At least 362 people died and many more were injured during the course of the disasters that included:

1 freeze;
1 drought (affected multiple areas);
1 wildfire (affected multiple areas);
2 floods;
3 major hurricanes (Harvey, Irma and Maria); and
8 severe storms.

The biggest newsmakers include the western U.S. wildfires that caused damages tallying $18 billion — triple the previous U.S. record. Losses from Hurricane Harvey exceeded $125 billion, which ranked second only to Hurricane Katrina, the costliest storm in the 38-year period of record. Hurricanes Maria and Irma had total damages of $90 billion and $50 billion, respectively. Hurricane Maria now ranks as third costliest weather and climate disaster on record for the nation, with Irma coming in close behind as fifth costliest.

Since 1980, the U.S. has sustained 219 weather and climate disasters that have exceeded $1.5 trillion in overall damages to date.

Billion Dollar Disasters
Billion Dollar Disasters

16 weather and climate disasters each with losses exceeding $1 billion

During 2017, the U.S. experienced a historic year of weather and climate disasters. In total, the U.S. was impacted by 16 separate billion-dollar disaster events tying 2011 for the record number of billion-dollar disasters for an entire calendar year. In fact, 2017 arguably has more events than 2011 given that our analysis traditionally counts all U.S. billion-dollar wildfires, as regional-scale, seasonal events, not as multiple isolated events.

More notable than the high frequency of these events is the cumulative cost, which exceeds $300 billion in 2017 — a new U.S. annual record. The cumulative damage of these 16 U.S. events during 2017 is $306.2 billion, which shatters the previous U.S. annual record cost of $214.8 billion (CPI-adjusted), established in 2005 due to the impacts of Hurricanes Dennis, Katrina, Rita and Wilma.

bookmark_borderBomb Cyclone: Extreme Weather Events

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Bomb Cyclone Storm on January 4, 2018 off the Northeastern Shore
Bomb Cyclone Storm on January 4, 2018 off the Northeastern Shore

“‘Bomb cyclone’ blasting East Coast before polar vortex uncorks tremendous cold late this week.  The most severe winter weather yet will assault the area late this week.” — washingtonpost.com (January 3, 2018)

The bomb cyclone blizzard was a 1,000 mile wide Nor’easter classified as a “bomb cyclone” because of its sharp drop in atmospheric pressure. “Bombogenesis, a popular term used by meteorologists, occurs when a midlatitude cyclone rapidly intensifies, dropping at least 24 millibars over 24 hours,” said NOAA.

“We are not saying that the Earth’s temperature is just going to rise. In general, as energy is added to a system, the fluctuations in the system increase. So, we expect more storms, more droughts, more wildfires, more floods, more fluctuations of all kinds. What we are saying is that weather conditions will become more volatile due to the impact of humans,” said Sidd Mukherjee and Daniel Brouse (2004)

“What use to be a once-in-a-hundred year event is now an annual event.” (2017)

“I think the public and many policymakers don’t really take those 100-year forecasts very seriously,” said Myles Allen, an Oxford scientist who is now one of the world’s leading experts in attribution science. “They are much more seriously interested in the question of what is happening now and why—which boils down to attribution.”

It use to be that scientists were reluctant to relate any single weather event to climate change; however, that has changed.

NOAA now issues a report for extreme weather events, “This report provides information on direct economic losses, deaths, and other impacts for numerous weather and climate disasters including tropical cyclones, floods, droughts and heat waves, severe storms (e.g., tornadoes, hail, and straight-line winds), wildfires, crop freeze events, and winter storms.”

The Bulletin of the American Meteorological Society now issues a special report each year assessing the impact of climate change on the previous year’s extreme events.

Scientific American reported, Myles Allen had hinted about “litigation two years before Hurricane Katrina occurred. In his Nature commentary, he mused about the possibility of massive class-action lawsuits—carrying the potential for “up to six billion plaintiffs” around the world—attempting to hold greenhouse gas emitters liable for damages.

Attribution studies could help to apportion the blame, he noted. For instance, he wrote, “If, at a given confidence level, past greenhouse-gas emissions have increased the risk of a flood tenfold, and that flood occurs, then we can attribute, at that confidence level, 90% of any damage to those past emissions.”

About 2017, NPR reported, “This year will go down in history for its extreme weather. Researchers have now definitively attributed three major extreme weather events to climate change.”

LINDA WERTHEIMER, HOST:

If you’re listening to this program from the Midwest or East Coast, well, I hope you’re nice and warm inside your house or car. President Trump took note of the frigid temperatures in the East this holiday season with this tweet – perhaps we could use a little bit of that good, old global warming.

Climate scientists note that while parts of the U.S. are much colder than average now, the world as a whole this week is warmer than the average over recent decades. One thing climate scientists have long been reluctant to say is that specific extreme weather events are the result of climate change. But NPR’s Christopher Joyce says a little-noticed study this past year did prove a link.

CHRISTOPHER JOYCE, BYLINE: This was this – a study that determined that, yes, looking at events in 2016, 27 of them – they found three that were so off the charts that they had to be the result of what we have done to the planet. They’re just beyond what is expected to be a natural event.

WERTHEIMER: What are they? What are the three events?

JOYCE: Well, one was the incredible heat that we experienced – the average temperature around the globe in 2016. It was 1.7 degrees Fahrenheit above the average in the 20th century. And that is just enormous. The second one – extreme heat waves in Asia, especially India and Pakistan. Hundreds of people died. The temperatures were just beyond belief. And the third one – one not noticed that much – but something called the blob, which was a section of water in the Bering Sea off the coast of Alaska that was just unusually warm – again, so warm that it’s just beyond what could be modeled as being – as happening in a natural world.

WERTHEIMER: But still, how do they know that this was not just weird weather – certainly, extreme, unexpected, unusual?

JOYCE: You know, again, I have to use the word model, which people are afraid of. But they’re computer models. And what you basically do is you recreate the world as it was before the Industrial Revolution and certainly before the mid-20th century when we started warming it up. And you put in all of the atmosphere. You put in the oceans, the circulation, the temperature. And you sort of create this world before we changed it. And then you create another model of the world we’re in. And you take these events, and you put them in that model of what the world used to be like. And you can tell that they couldn’t have been created by the forces that were at work before we warmed the planet.

WERTHEIMER: So those three things could not have happened absent global warming.

JOYCE: Yeah. I talked to one of the scientists who did the work – who compiled the work – Stephanie Herring of the National Oceanic and Atmospheric Administration. And this is how she put it.

(SOUNDBITE OF ARCHIVED RECORDING)

STEPHANIE HERRING: Not even one in a million. They cannot replicate them in a world without climate change is what the scientists are saying. It’s a big result, yes. It’s – again, you know, we’ve been doing this for six years, 131 papers. This is our first time seeing this.

bookmark_borderClimate Change And Credit

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by Daniel Brouse

Part of a series of articles on Climate Change And Flood Insurance

Homeowners living in flood plain have learned the hard way that climate change has effected their ability to get a mortgage. As the sea level rises and extreme weather events intensify, homeowners have found their insurance rates increasing or their total inability to obtain insurance coverage. Without insurance it is very, very hard to get a mortgage.

Moody’s credit ratings are now going to have a similar impact on municipalities. “What we want people to realize is: If you’re exposed, we know that. We’re going to ask questions about what you’re doing to mitigate that exposure,” Lenny Jones, a managing director at Moody’s, said in an interview. “That’s taken into your credit ratings.”

Bloomberg news agency reports:

In its report, Moody’s lists six indicators it uses “to assess the exposure and overall susceptibility of U.S. states to the physical effects of climate change.” They include the share of economic activity that comes from coastal areas, hurricane and extreme-weather damage as a share of the economy, and the share of homes in a flood plain.

Based on those overall risks, Texas, Florida, Georgia and Mississippi are among the states most at risk from climate change. Moody’s didn’t identify which cities or municipalities were most exposed.

“If I was a city official, I’d be asking a whole lot of questions about what vulnerabilities their community has, and how each new proposed development adds to that vulnerability,” said Rob Moore, a senior policy analyst at the Natural Resources Defense Council. “Because at some point, your creditors certainly will.”

Real Estate and the Rising Sea Level
Top 5 Risks
How Do We Handle Flood Risk?
Senegal Forecasts Climate Change Changes
Biloxi-Chitimacha-Choctaw Indians Climate Change Refugees
Atlantic City Going Under
Biggert Waters Flood Insurance Reform Act of 2012
Flood Insurance Reform 2011
About Flood Insurance
Who Pays For Flood Losses?
Floodplain Maps Force Towns Into Tricky Waters
Head of the Federal Flood Insurance Program Resigns
Sacramento And FEMA Fight On Flood Insurance
Global Warming

 

bookmark_borderWildfires: Increase In Extreme Weather

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The Membrane Domain started conducting global warming experiments in the 1990’s. It was about 1997 when we suggested the climate in Pennsylvania would turn more like Florida and the climate in California would turn more like Hades. The change wasn’t predicted to take place for hundreds of years. Now, only twenty years later, Pennsylvania has hot humid weather in October and California is on fire.

The Los Angeles Times entitled their article “The climate-change fire alarm from Northern California”. “These kinds of catastrophes have happened and they’ll continue to happen.” Gov. Jerry Brown observed at a news briefing Wednesday. “That’s the way it is with a warming climate, dry weather and reducing moisture.”

The article goes on to say, “California is fortunate to have a governor who understands the perils of ignoring climate change and is aggressively pushing policies to mitigate its future harm. Unfortunately, that puts him at odds with a head-in-the-sand president who blithely disregards the obvious connection between the warming climate and the multiple federal disaster areas he’s been forced to declare in Texas, Florida, Puerto Rico and, now, California.”

An article in Scientific American is entitled “Scientists See Climate Change in California’s Wildfires”. The subtitle is “Strong winds and months of record-high temperatures have fueled the destructive fires.”

As humans add fuel to storm systems, weather will become more extreme.

bookmark_borderClimate Change Breaks Multiple Records with Global Impacts

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The World Meteorological Organization (WHO) issued a report that states records for 2016:

  • a record global temperature
  • exceptionally low sea ice
  • unabated sea level rise
  • ocean heat

Extreme weather and climate conditions have continued into 2017.

“This report confirms that the year 2016 was the warmest on record – a remarkable 1.1 °C above the pre-industrial period, which is 0.06 °C above the previous record set in 2015. This increase in global temperature is consistent with other changes occurring in the climate system,” said WMO Secretary-General Petteri Taalas.

“Globally averaged sea surface temperatures were also the warmest on record, global sea levels continued to rise, and Arctic sea-ice extent was well below average for most of the year,” he said.

“With levels of carbon dioxide in the atmosphere consistently breaking new records, the influence of human activities on the climate system has become more and more evident,” said Mr Taalas.

The report goes on to say: Global sea levels rose very strongly during the El Niño event, with the early 2016 values reaching new record highs. Global sea ice extent dropped more than 4 million square kilometres below average in November, an unprecedented anomaly for that month.

The very warm ocean temperatures contributed to significant coral bleaching and mortality was reported in many tropical waters, with important impacts on marine food chains, ecosystems and fisheries.

Carbon dioxide levels in the atmosphere reached the symbolic benchmark of 400 parts per millions in 2015 – the latest year for which WMO global figures are available – and will not fall below that level for many generations to come because of the long-lasting nature of CO2.

Noteworthy extreme events in 2016 included severe droughts that brought food insecurity to millions in southern and eastern Africa and Central America. Hurricane Matthew caused widespread suffering in Haiti as the first category 4 storm to make landfall since 1963, and inflicted significant economic losses in the United States of America, while heavy rains and floods affected eastern and southern Asia.

The extreme weather continues in 2017.
In addition to the report on 2016, the WHO issued a supplement for 2017:
“Even without a strong El Niño in 2017, we are seeing other remarkable changes across the planet that are challenging the limits of our understanding of the climate system. We are now in truly uncharted territory,” said World Climate Research Programme Director David Carlson.

At least three times so far this winter, the Arctic has witnessed the Polar equivalent of a heatwave, with powerful Atlantic storms driving an influx of warm, moist air. This meant that at the height of the Arctic winter and the sea ice refreezing period, there were days which were actually close to melting point. Antarctic sea ice has also been at a record low, in contrast to the trend in recent years.

Scientific research indicates that changes in the Arctic and melting sea ice is leading to a shift in wider oceanic and atmospheric circulation patterns. This is affecting weather in other parts of the world because of waves in the jet stream – the fast moving band of air which helps regulate temperatures.

Thus, some areas, including Canada and much of the USA, were unusually balmy, whilst others, including parts of the Arabian peninsula and North Africa, were unusually cold in early 2017.

In the USA alone, 11,743 warm temperature records were broken or tied in February, according to the US National Oceanic and Atmospheric Administration. Prolonged and extreme heat in January and February affected New South Wales, southern Queensland, South Australia and northern Victoria, and saw many new temperature records.

Highlights of the 2016 Statement

Global Temperatures:

2016’s warmth extended almost worldwide. Temperatures were above the 1961-90 average over the vast majority of the world’s land areas, the only significant exceptions being an area of South America centred on central Argentina, and parts of south-western Australia.

Mean annual temperatures at least 3 °C above the 1961-1990 average occurred in various high-latitude locations, particularly along the Russian coast and in Alaska and far north-western Canada, and on islands in the Barents and Norwegian Seas. In the high Arctic, Svalbard (Norway) Airport’s 2016 mean annual temperature of −0.1 °C was 6.5 °C above the 1961-1990 average, and 1.6 °C above the previous record.

Outside the Arctic, 2016’s warmth was more notable for its consistency across the globe than for its extreme nature in individual locations.

Oceans

Globally averaged sea surface temperatures in 2016 were the warmest on record. The anomalies were strongest in the early months of 2016.

Global ocean heat content was the second-highest on record after 2015. It reached new record highs in the northern hemisphere, but was cooler in the southern hemisphere.

Globally, sea level has risen by 20 cm since the start of the twentieth century, mostly due to thermal expansion of the oceans and melting of glaciers and ice caps. Global sea levels rose very strongly during the 2015/2016 El Niño, rising about 15 millimetres between November 2014 to a new record high in February 2016. This was well above the post-1993 trend of 3 to 3.5 mm per year. From February to August, sea levels remained fairly stable as the influence of the El Niño declined. Final 2016 sea level data are not yet available at the time of writing.

Arctic sea ice

The seasonal maximum, of 14.52 million square kilometres on 24 March, was the lowest in the 1979-2016 satellite record. The 2016 autumn freeze-up was exceptionally slow – with sea ice extent even contracting for a few days in mid-November.

Precipitation

Much of southern Africa began the year in severe drought. For the second year in succession, rainfall was widely 20 to 60% below average for the summer rainy season (October to April) in 2015/2016. The World Food Programme estimating that 18.2 million people would require emergency assistance by early 2017.

Provisional figures showed 2016 was the driest on record over the Amazon Basin, and there was also significant drought in north-east Brazil.  El Niño brought drought conditions elsewhere in Central America and northern South America.

The Yangtze basin in China experienced, overall, its most significant flood season since 1999, with some tributaries experiencing record flood levels. Averaged over China as a whole, it was the wettest year on record, with national mean rainfall of 730 mm being 16% above the long-term average.

Heatwaves

The year started with an extreme heatwave in southern Africa in the first week of January. On 7 January, it reached 42.7 °C at Pretoria and 38.9 °C at Johannesburg, both of which were 3 °C or more above the all-time records at those sites.

Extreme heat also affected South and South-East Asia in April and May, prior to the start of the summer monsoon. South-East Asia was badly affected in April. A national record of 44.6 °C was set at Mae Hong Son, Thailand, on 28 April, and 51.0 °C was observed on 19 May at Phalodi, the highest temperature on record for India.

Record or near-record temperatures occurred in parts of the Middle East and north Africa. The highest temperature observed was 54.0 °C at Mitribah (Kuwait) on 21 July which (subject to ratification) will be the highest temperature on record for Asia. Other extremely high temperatures included 53.9 °C at Basra (Iraq) and 53.0 °C at Delhoran (Islamic Republic of Iran – a national record), both on 22 July, whilst significant high temperatures were also reported in Morocco, Tunisia, Libya and the United Arab Emirates.

A late-season heatwave affected many parts of western and central Europe in the first half of September. In southern Spain, 45.4 °C was recorded at Cordoba on 6 September.

ABOUT WMO
WMO is a specialized agency of the United Nations (UN) with 191 Member States and Territories. It is the UN system’s authoritative voice on the state and behaviour of the Earth’s atmosphere, its interaction with the land and oceans, the weather and climate it produces and the resulting distribution of water resources.

Additional References
Guide To Climate Change
The Human Induced Climate Change Experiment

bookmark_borderClimate Change, Extreme Weather and Toxic Crops

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by Daniel Brouse

The United Nations Environment Programme (UNEP) has released a report that examines how climate change is increasing the toxicity of crops.

Crop Toxicity
Extreme weather events, such as “drought and high temperatures, can trigger the accumulation in crops of chemical compounds that are toxic to animals and humans.”

The report goes on to say: Wheat, barley, maize (corn) and millet are among the crops most susceptible to nitrate accumulation, which is caused by prolonged drought. Acute nitrate poisoning in animals can lead to miscarriage, asphyxiation and death, ruining the lives of smallholder farmers and herders.

Heavy rains that break prolonged drought can also result in the dangerous accumulation of another toxic compound called hydrogen cyanide or prussic acid in crops like flax, maize, sorghum, arrow grass, cherries and apples.

Aflatoxins, which are fungal toxins that can cause cancer and stunt foetal growth, are another emerging problem in crops. The risk of aflatoxin contamination, especially in maize, is expected to increase in higher latitudes due to rising temperatures. A recent study predicts that this toxin will become a food safety issue for Europe, especially in the most likely scenario of a 2oC rise in global temperatures.

The report highlights two critical issues associated with climate change – loss and damage. Given the delays in the last 25 years in mitigating and adapting to climate change, scientific evidence suggests that losses and damages from climate change are inevitable, with profound consequences for ecosystems, people, assets and economies. This is already happening. The heat waves of 2003 are a good example of what happens when efforts to mitigate and adapt to changes in the climate fail: 30,000 people died, glaciers decreased, permafrost thawed and the European Union’s agricultural sector lost $14.7 billion.

bookmark_borderTemperature Reaches 123 Degrees in India

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The temperature went over 123 degrees (50C) in India. This was the highest temperature ever recorded in the country.

“Fishermen are advised not to venture into the sea along and off Tamil Nadu and Puducherry during the next 24 hours, along and off Andhra Pradesh coast during the next 48 hours and also and off the Odisha coast on 19th and 20th of May,” the IMD (India Meteorological Department) said in an advisory on Wednesday. –

Deutsche Welle reported, “The heat wave comes as India suffers its worst drought in decades, affecting around 330 million people. Drinking water is running short in many areas and poor rains have prompted the central government to send water trains to regions affected by drought. Hundreds of people have died and crops have been destroyed in several states.”

bookmark_borderBillion People Face Global Flooding

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The BBC reports, a British aid charity is warning that by 2060 more than a billion people worldwide will live in cities at risk of catastrophic flooding as a result of climate change. A study by Christian Aid says the US, China and India are among the countries most threatened. It says the Indian cities of Kolkata and Mumbai will be most at risk.

The eight most vulnerable cities on the list are all in Asia, followed by Miami in the US. The report urges governments to take action to reduce global warming and invest in disaster reduction programs.

Dr Alison Doig, the report’s author, told the BBC World Service that people living in large coastal cities were particularly at risk.

“I think it’s cities like Kolkata, Dakar, the big mega-cities of the south and the emerging economies where the people are most vulnerable to exposure to sea-level rises and to higher rain events,” she said.

“Flooding in these cities can cause massive damage, but can also threaten life.”

“The whole of Florida is totally vulnerable,” she said.

“It is so low-lying, it is virtually swampland reclaimed. So significant climate change… raising water half to a full metre this century, will take out an awful lot of Florida and a significant amount of Miami.”

The study says that the priority should be to rapidly reduce carbon emissions and limit temperature increase by switching from fossil fuels to low-carbon energy.

It says vulnerable communities must be helped by better protecting homes and livelihoods.

The study also calls for international systems to help communities recover from devastating storms and floods.

Dr Doig warned that Florida was likely to suffer extensive flooding.