Tag: tipping cascades

bookmark_borderCoral Reefs’ Tipping Point

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by Daniel Brouse
February 14, 2024

Coral reefs confront unprecedented challenges arising from various stressors, many of which are directly tied to human activities. Some of these stressors possess critical tipping points, surpassing which can lead to the collapse of coral ecosystems. According to the European Geosciences Union’s statement on January 2, 2024, specific tipping points include a temperature increase of 1.2℃ above pre-industrial levels and atmospheric CO2 concentrations exceeding 350 parts per million. Disturbingly, as of February 2024, the Earth’s yearly average temperature has already risen to +1.5℃, underscoring the urgency of addressing climate-related threats to coral reefs.

Climate change is having significant and detrimental effects on coral reefs around the world. Some of the key impacts include:

  1. Coral Bleaching:
    • One of the most immediate and visible impacts of climate change on coral reefs is coral bleaching. Elevated sea temperatures cause corals to expel the symbiotic algae (zooxanthellae) living within their tissues. Without these algae, corals lose their vibrant colors and become more susceptible to stress, disease, and death. While corals can recover from mild bleaching events, severe or prolonged bleaching can lead to widespread coral mortality.
  2. Ocean Acidification:
    • Increased carbon dioxide (CO2) levels in the atmosphere not only contribute to global warming but also lead to ocean acidification. The absorption of excess CO2 by the oceans results in a decrease in pH, making the water more acidic. This acidification can weaken coral skeletons and hinder the ability of corals to build and maintain their calcium carbonate structures.
  3. Sea Level Rise:
    • Rising global temperatures contribute to the melting of polar ice caps and glaciers, causing sea levels to rise. Elevated sea levels can lead to increased stress on coral reefs, especially those located in shallow waters. This can result in reduced sunlight reaching the corals and increased sedimentation, impacting their growth and survival.
  4. Extreme Weather Events:
    • Climate change is linked to an increase in the frequency and intensity of extreme weather events, such as hurricanes and cyclones. These events can physically damage coral reefs by causing coral breakage, dislodgment, and destruction of the reef structure. The recovery time for damaged reefs is often extended, making them more vulnerable to subsequent disturbances.
  5. Changes in Ocean Circulation:
    • Climate change can alter ocean currents and circulation patterns. Changes in water flow can affect the distribution of nutrients and impact the resilience of coral reefs. Some regions may experience altered temperature regimes, nutrient imbalances, and disruptions in the supply of food sources for corals and their associated ecosystems.
  6. Shifts in Coral Species Distribution:
    • As sea temperatures change and habitats are modified, the distribution of coral species may shift. Some species may migrate to cooler waters, while others may struggle to adapt or face local extinctions. These shifts can disrupt the balance of ecosystems and affect the biodiversity associated with coral reefs.

The cumulative impact of these climate-related stressors poses a severe threat to coral reefs worldwide. It’s crucial to address the root causes of climate change and implement conservation measures to enhance the resilience of coral ecosystems. Protection of coral reefs involves both local and global efforts, including sustainable fishing practices, marine protected areas, reducing greenhouse gas emissions, and promoting coral reef restoration initiatives.

Coral reef ecosystems can be influenced by several feedback loops that contribute to reaching tipping points. These feedback loops often involve interactions between various environmental stressors and the responses of coral reefs. Here are some feedback loops associated with the coral reef tipping point:

  1. Coral Bleaching Feedback Loop:
    • Mechanism: Elevated sea temperatures, driven by climate change, can trigger coral bleaching, where corals expel their symbiotic algae.
    • Effect: As bleaching occurs, corals become stressed and more susceptible to diseases. If bleaching is severe or occurs frequently, it weakens coral resilience and can lead to widespread coral mortality, reducing the ability of the reef to recover.
  2. Ocean Acidification and Coral Growth Feedback Loop:
    • Mechanism: Increased atmospheric carbon dioxide (CO2) leads to ocean acidification, hindering the ability of corals to build and maintain their calcium carbonate structures.
    • Effect: Weakened coral skeletons make corals more vulnerable to physical damage and limit their capacity to recover from disturbances. This feedback loop can contribute to a decline in overall coral reef health.
  3. Storm Damage and Reef Structure Feedback Loop:
    • Mechanism: Intense tropical storms, hurricanes, or cyclones, influenced by climate change, can cause physical damage to coral reefs.
    • Effect: Damaged coral structures provide less protection for the reef against future storms. If storms become more frequent or severe, the cumulative impact can compromise the structural integrity of the reef and hinder recovery.
  4. Overfishing and Algae Overgrowth Feedback Loop:
    • Mechanism: Overfishing of herbivorous fish, such as parrotfish, reduces their population, leading to increased algae growth on coral reefs.
    • Effect: Algae can outcompete corals for space, hindering coral growth and recovery. Reduced herbivory exacerbates the overgrowth of algae, creating a feedback loop that undermines the resilience of the coral reef ecosystem.
  5. Disease Spread and Coral Health Feedback Loop:
    • Mechanism: Climate change and environmental stressors can weaken coral health, making them more susceptible to diseases.
    • Effect: As diseases spread among stressed corals, the overall health of the reef declines. Weakened corals are less able to withstand additional stressors, leading to a feedback loop of declining health and increased vulnerability.
  6. Loss of Biodiversity and Ecosystem Function Feedback Loop:
    • Mechanism: Environmental stressors, such as coral bleaching and disease, can lead to the loss of key species and a decline in overall biodiversity on the reef.
    • Effect: A reduction in biodiversity weakens the resilience and functioning of the coral reef ecosystem. This can create a feedback loop where the loss of key species further compromises the ability of the reef to recover from disturbances.

Mitigating these feedback loops requires comprehensive conservation strategies, including reducing greenhouse gas emissions, implementing sustainable fishing practices, establishing marine protected areas, and addressing local stressors to enhance the resilience of coral reefs.

ALSO SEE:

Toppled Tipping Points: The Domino Effect / Brouse and Mukherjee (2023)

Sea-level Rise: Greenland and the Collapse of the East Antarctic Ice Sheet / Mukherjee and Brouse (2022 and 2023)

Sea Level Rise: Then and Now / Mukherjee and Brouse (2023)

Feedback Loops / Daniel Brouse and Sidd Mukherjee (2016)

The Human Induced Climate Change Experiment

bookmark_borderTipping Cascades, Social-Ecological Systems, and the Hottest Year in History

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by Daniel Brouse
January 9, 2024

Human induced climate change is an exponential component of an unordered system (chaos theory). That means global warming is accelerating at a rapid rate in a complex way.

Unfortunately, even scientists are failing to see (let alone forecast) the rapid acceleration in climate change. Due to their complexity, the impacts of the Domino Effect are being underestimated. Tipping points are Critical Milestones that directly impact the rate of acceleration in climate change by multiplying the number and intensity of feedback loops. The Domino Effect is also known as “tipping cascades” in climate science. Cascading impacts in relation to tipping points include cascading impacts across biogeophysical and social systems. Until recently, scientist have been drastically underestimating the social-ecological systems. The University of Exeter reports, “There is a notable lack of topic clusters dedicated to how humans will be impacted by climate-related tipping cascades.”

The Age of Loss and Damage is a new way of thinking about economics by combining economics, climate science, statistics, and physics. Until now, economic models have been unfit to capture the full extent of climate damage. Traditionally, “integrated assessment models” (IAMs) were used to forecast “shock” events. IAMs use “quadratic function” to calculate GDP losses by squaring the temperature change, yet ignore other methods (such as the exponential function) that are better suited for rapid change. “Climate change is fundamentally different to other shocks because once it has hit, it doesn’t go away,” said Thierry Philipponnat, author of a report by Finance Watch, a Brussels-based public interest NGO on financial issues. “And if the fundamental assumption is flawed, all the rest makes little sense — if any.”

Reuters reported, “Critics say this (IAMs) choice is doomed to underplay the likely impact – particularly if the planet hits environmental tipping points in which damage is not only irreversible but happens at an ever-accelerating rate.” Thierry Philipponnat’s report, Finance in a Hot House World, concludes: “Climate risk is growing to disruptive levels throughout the financial system and the guardians of financial stability urgently need to adapt their tools to regain control.” The report calls for economic models that do not mislead, scenario analyses that prepare the market, and a new prudential tool to address the build-up of systemic climate risk.

Traditional economics is based upon the “costs and benefits” to society. Since there are no known long-term benefits of climate change to society, the Age of Loss and Damage economics focuses on the exponential costs of climate change to society.
— from The Age of Loss and Damage / Brouse (2023)

2023: The Hottest Year in Human History
2023 was a wake-up call to both biogeophysical and social-ecological scientists. The record breaking physical and economical impacts could be felt worldwide. The record warming year was seventeen times greater than any other record increase in history. Typically record breaking temperatures are measured in 100th degrees. There were also 200 consecutive days of record breaking temperatures. Typically there are one or two record breaking days in row. The increase in intensity and frequency of record breaking heat requires forecasting models to be recast.

2023 Biogeophysical Records

Global temperatures reached exceptionally high levels in 2023. The Copernicus Climate Change Service (C3S), implemented by the European Centre for Medium-Range Weather Forecasts on behalf of the European Commission with funding from the EU, monitored several key climate indicators throughout the year, reporting on record-breaking conditions such as the hottest month on record and daily global temperature averages briefly surpassing pre-industrial levels by more than 2°C. Unprecedented global temperatures from June onwards led 2023 to become the warmest year on record – overtaking by a large margin 2016, the previous warmest year.

Highlights: 

  • 2023 is confirmed as the warmest calendar year in global temperature data records going back to 1850
  • 2023 had a global average temperature of 14.98°C, 0.17°C higher than the previous highest annual value in 2016
  • 2023 was 0.60°C warmer than the 1991-2020 average and 1.48°C warmer than the 1850-1900 pre-industrial level
  • It is likely that a 12-month period ending in January or February 2024 will exceed 1.5°C above the pre-industrial level
  • 2023 marks the first time on record that every day within a year has exceeded 1°C above the 1850-1900 pre-industrial level. Close to 50% of days were more than 1.5°C warmer then the 1850-1900 level, and two days in November were, for the first time, more than 2°C warmer.
  • Annual average air temperatures were the warmest on record, or close to the warmest, over sizeable parts of all ocean basins and all continents except Australia
  • Each month from June to December in 2023 was warmer than the corresponding month in any previous year
  • July and August 2023 were the warmest two months on record. Boreal summer (June-August) was also the warmest season on record
  • September 2023 was the month with a temperature deviation above the 1991–2020 average larger than any month in the ERA5 dataset
  • December 2023 was the warmest December on record globally, with an average temperature of 13.51°C, 0.85°C above the 1991-2020 average and 1.78°C above the 1850-1900 level for the month. You can access information specific for December 2023 in our monthly bulletin
  • Global average sea surface temperatures (SSTs) remained persistently and unusually high, reaching record levels for the time of year from April through December
  • 2023 saw a transition to El Niño. In spring 2023, La Niña came to an end and El Niño conditions began to develop, with the WMO declaring the onset of El Niño in early July.
  • High SSTs in most ocean basins, and in particular in the North Atlantic, played an important role in the record-breaking global SSTs
  • The unprecedented SSTs were associated with marine heatwaves around the globe, including in parts of the Mediterranean, Gulf of Mexico and the Caribbean, Indian Ocean and North Pacific, and much of the North Atlantic
  • 2023 was remarkable for Antarctic sea ice: it reached record low extents for the corresponding time of the year in 8 months. Both the daily and monthly extents reached all-time minima in February 2023
  • Arctic sea ice extent at its annual peak in March ranked amongst the four lowest for the time of the year in the satellite record. The annual minimum in September was the sixth-lowest
  • The atmospheric concentrations of carbon dioxide and methane continued to increase and reached record levels in 2023, reaching 419 ppm and 1902 ppb respectively. Carbon dioxide concentrations in 2023 were 2.4 ppm higher than in 2022 and methane concentrations increased by 11 ppb.
  • A large number of extreme events were recorded across the globe, including heatwaves, floods, droughts and wildfires. Estimated global wildfire carbon emissions in 2023 increased by 30% with respect to 2022 driven largely by persistent wildfires in Canada

2023 Social-Ecological Records

NOAA: 2023 A historic year of U.S. billion-dollar weather and climate disasters

In 2023, the U.S. experienced 28 separate weather and climate disasters costing at least 1 billion dollars. That number puts 2023 into first place for the highest number of billion-dollar disasters in a calendar year and included:

  • 1 winter storm/cold wave event (across the northeast U.S. in early-February).
  • 1 wildfire event (firestorm destroying town of Lahaina on Maui Island of Hawaii).
  • 1 drought and heat wave event (focused across the central and southern U.S.).
  • 4 flooding events (in California, Florida, and across the eastern and northeastern U.S.).
  • 2 tornado outbreaks (across the central and eastern U.S.).
  • 2 tropical cyclones (Idalia in Florida and Typhoon Mawar in Guam).
  • 17 severe weather/hail events (across many parts of the country).

2023 was also deadly, causing at least 492 direct or indirect fatalities — the 8th most disaster-related fatalities for the contiguous U.S. since 1980.

What Can I Do?
There are plenty of things you can do to help save the planet. Stop using fossil fuels. Consume less. Love more. Here is a list of additional actions you can take.

ALSO SEE: Climate Change: Rate of Acceleration / Brouse and Mukherjee (2023)

The Human Induced Climate Change Experiment