The U.N. has released a report entitled, “Extreme Weather Continues in 2018 – a Continuing Call to Climate Action”.
Addressing the dangers associated with extreme weather conditions, the Executive Secretary of the UN Climate Change Patricia Espinosa said: “We must keep an eye on the future. As the superstorms and monsoon flooding of last year and the extreme heat and extreme cold of this year show – we still have a long way to go to deliver on the promise of the Paris Climate Change Agreement”.
This year, record warmth was observed across parts of North America, Europe and Asia, as well as the Atlantic, Pacific and Indian Oceans. Record cold May temperatures were limited to northeastern Canada and the northern Atlantic Ocean, off the southern coast of Greenland.
The study published in the journal Nature showed that ice losses from Antarctica are causing sea levels to rise faster today than at any time in the past 25 years. Results of the Ice Sheet Mass Balance Inter-Comparison Exercise (IMBIE).
According to NASA, “Antarctica’s potential contribution to global sea level rise from its land-held ice is almost 7.5 times greater than all other sources of land-held ice in the world combined. The continent stores enough frozen water to raise global sea levels by 190 feet (58 meters), if it were to melt entirely. Knowing how much ice it’s losing is key to understanding the impacts of climate change now and its pace in the future.”
NOAA points to climate change as part of the problem causing the largest wildfires in California.
Daytime high temperatures were well above average across much of the western United States in July, but it was overnight low temperatures that were really extreme in large areas of California—where firefighters are battling multiple wildfires—and the Great Basin, and in isolated pockets of Colorado and the Southwest.
As the NCEI’s Deke Arndt has blogged about before, nighttime low temperatures are increasing faster than daytime high temperatures across most of the contiguous United States. For much of the West and Southwest, July’s record-breaking nighttime heat is a new highpoint in a long-term trend—one that has rapidly accelerated in recent decades. In California, average overnight low temperature in July rose by 0.3°F per decade over the historical record (1895-2018), but since 2000, the pace of warming has accelerated to 1.3°F per decade.
Average July minimum temperatures (overnight lows) in California (light orange line) from 1895–2018. The trend over the historical record is shown in dark orange, and the recent trend (2000-2018) is shown in red. The twentieth-century average is shown with a gray line. NOAA Climate.gov graph, based on data from NCEI’s Climate at a Glance.
According to Tim Brown, director of NOAA’s Western Region Climate Center (WRCC), it’s a pattern that has serious consequences for wildfires and those who combat them. When temperatures cool off overnight, it’s not just a physical relief for firefighters who may be working in conditions that push the limits of human endurance; fire behavior itself relaxes as temperatures drop, winds grow calmer, and relative humidity rises. He explained via email,
Moisture in dead vegetation continuously tries to reach equilibrium with atmospheric moisture. So if nighttime temperature is staying warmer, then the humidity is lower, and the fuels stay drier. A dead fuel moisture reduction of a few percent can increase flammability, flame length, and subsequent overall fire behavior.
When fires remain active at night, it can increase both the time to containment and total burned area, while also affecting public health and safety through more smoke production and lower air quality. Brown says that qualitatively, there seems to be an increase in firefighters’ reports of active nighttime fire behavior since around 2000. He and other researchers are currently investigating whether that relationship can be confirmed quantitatively.
NASA Aqua satellite image of the Ranch and River Fires in Northern California on August 6, 2018, with a pall of smoke spreading to the east. These fires are part of the Mendocino Complex Fire, which has become the largest fire in California history. Extreme fire activity in the state was exacerbated by record-warm overnight low temperatures in July. Image from NASA Worldview website.
Nighttime warming has consequences for other aspects of public health. WRCC climatologist Nina Oakley pointed out via email that the South Coast region of California is experiencing the largest warming trends in nighttime temperatures, according to an environmental health hazard report from the California Environmental Protection Agency. In many communities in the region, air conditioning—rarely needed in the past—is uncommon. In addition, since 2000, heat waves in California have become more humid. In the report, experts offered a warning about the change:
People, animals, and plants that are adapted to California’s traditionally dry daytime heat and nighttime cooling are unable to recover from extreme heat, especially when humidity is high at night. The increase in nighttime heat waves presents an additional risk factor for vulnerable populations.
The rapid increase in the rate of warming in California and other parts of the U.S. West since the start of the new century is a sharp reminder that we can’t necessarily count on the future changing as slowly as the past. Asked about the July nighttime heat in California, California state climatologist Mike Anderson answered via email, “As for the past decade or two, we have noticed observations have looked different than the rest of the historical record. We are consistently sampling at the warm edge of the historical distribution now, and expectations are for that to continue, with new records being set with increasing frequency in the coming years.”
Parts of Pennsylvania recorded record rainfall during the summer of 2018 with frequent “tropical downpours” delivering thirteen or more inches of rain in a 5 day period. The Penn Environment Organization released a report entitled, “Hitting Close to Home | Global Warming is Fueling Extreme Weather Across the U.S.”
Weather-related disasters affect millions
- Since September 2010, counties housing 84 percent of the total Pennsylvania population (over 10 million residents) were affected by federally-declared weather disasters.
- Pennsylvania experienced five weather-related disasters, including severe storms, tornadoes, floods, and tropical storms since September 2010.
Extreme weather causes widespread destruction
- In February 2015 a large winter storm and associated cold wave impacted many central, eastern and northeastern states, including Pennsylvania. The storm and cold wave caused at least 30 deaths and the total estimated costs were over $1 billion in the affected region.
- In October 2012 Hurricane Sandy caused extensive damage to several states, including Pennsylvania from wind, rain, and heavy snow. Hurricane Sandy caused at least 159 deaths and the total estimated costs were $67.6 billion in the affected regions.
- Since 2010, extreme weather events have caused at least 30 power outages in Pennsylvania, including one outage that lasted 10 days in 2012 during Hurricane Sandy. [3]
Weather extremes are becoming more common
Globally, 2015 was Earth’s hottest year on record, surpassing 2014. [4] Many types of extreme weather are expected to become more frequent or severe in a warming world, which could lead to more weather-related disasters.
- Tropical Storms and Hurricanes: Global warming has the potential to make tropical storms more destructive. Hurricanes and other coastal storms are likely to be more powerful [5] and rainier, [6] while storm surges could be more destructive as sea levels rise. [7]
- Heavy Rain and Snow: Extreme precipitation is already increasing; continued trends could increase the risk of intense downpours, heavy snowstorms and severe flooding. [8]
- Droughts and Wildfires: While global warming is anticipated to bring more rain to some areas, it will also likely elevate temperatures and extend dry spells. The potential for stronger drought—and greater area burned by wildfires—will increase, particularly in the West and Southwest.
Every year the World Economic Forum publishes the Global Risks Report. This year’s report suggests that experts anticipate another year of heightened risk. From the approximately 1000 respondents of the annual Global Risks Perception Survey, 59% expect an intensified risk, compared to 7% pointing to declining risks.
Environmental risks have grown in prominence over the 13-year history of the Global Risks Report. This trend continues in the 2018 report. All five risks in the environmental category are ranked higher than average in both likelihood and impact over a 10-year horizon.
“Extreme weather events” and “Natural disasters” rank among the top three risks in terms of likelihood and impact. “Failure of climate-change mitigation and adaptation” ranks among the top five.