Jeff’s Climate Classroom: Climate Tipping Points threaten ‘irreversible changes’
TAMPA, Fla. (WFLA) — In recent days the most comprehensive report to date on Earth’s climate system “Tipping Points” was released.
The report warns, “Environmental stresses could become so severe that large parts of the natural world are unable to maintain their current state, leading to abrupt and/or irreversible changes.”
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Some of these tipping points may not be very far off. The team of 200 researchers led by Dr. Tim Lenton at the University of Exeter, says climate change has already put five major tipping systems at risk of being crossed at the present level of global warming: the Greenland and West Antarctic ice sheets, warm-water coral reefs, North Atlantic Subpolar Gyre circulation, and permafrost regions.
The report warns, “These tipping points pose threats of a magnitude never faced by humanity”.
A tipping point can be described as a threshold in a system in which a small change – like a trigger – causes the system’s rate of change to increase abruptly, and that change will continue even if that forcing is removed until a state is reached. Once a system passes a threshold the changes are often impossible to reverse.
The report states: “These threats could materialize in the coming decades and at lower levels of global warming than previously thought. They could be catastrophic, including global-scale loss of capacity to grow major staple crops. Triggering one Earth system tipping point could trigger another, causing a domino effect of accelerating and unmanageable damage. Tipping points show that the overall threat posed by the climate and ecological crisis is far more severe than is commonly understood.”
The average global temperature of Earth has warmed by 1.3 degrees Celsius (2.3 degrees Fahrenheit) since the late 1800s, due mainly to increases in atmospheric heat-trapping greenhouse gases from the burning of fossil fuels. While that may not sound like a lot, our current warming rate is 50 times faster than the natural warming rate which proceeded during the most recent ice age.
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The excess heat energy in the system is causing the breakdown of certain Earth systems. One local Florida example is coral reefs. This summer an unprecedented marine heatwave annihilated much of what is left of the Florida Keys Coral Reef Tract. While this summer’s heat was off the charts, the trend is clear. Since 2011 some degree of coral bleaching has been happening every summer as waters continue to warm.
Since coral reefs form a foundation of life in the ocean, losing these reefs threatens the health of ocean life and species like humans who rely on them.
Another example is the Greenland and West Antarctic ice sheets. In recent years, warmer-than-normal water has been undercutting and undermining floating ice shelfs. These floating ice shelves buttress the miles-thick ice that sits behind them on land.
Scientists warn that the destabilization of the ice shelves can trigger a collapse. A collapse can be a tipping point which then allows land ice to accelerate, flowing freely into the ocean.
Right now, before any potential collapse, the melting of ice and associated sea level rise is gradual. But in the event of a collapse, the change in the system would accelerate abruptly.
Once the ice from a glacier starts flowing freely from land into the ocean, that further destabilizes nearby glaciers, and more ice flows into the ocean. Thus, the once gradual process of ice melt and sea level rise becomes exponentially faster. Abrupt sea level rise would displace hundreds of millions of people, destabilizing humanity.
The report warns that tipping points in the climate system can multiply crises in the same way that the COVID-19 pandemic caused cascading stress to societies and economic systems globally. “These impacts could escalate to threaten the breakdown of economic, social, and political systems, triggering destructive tipping points in societies experiencing stresses beyond their ability to cope.”
While it may be too late to stop certain tipping points, the report says that stopping some threats is still possible, but it requires urgent global action. However, the authors warn that the global governance required to meet this challenge simply does not exist right now.
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The report also introduces a concept called “positive tipping points.” This refers to the rapid acceleration of climate solutions which can lead to a transformation towards sustainability.
The authors use the example of innovations, from targeted government action and/or private investment, which are now propelling the exponential uptake of renewable energy worldwide and reducing the cost to below that of fossil fuels for power generation. Or how the increase in electric vehicles lowers the cost of battery storage technology and thus further lowers the cost of renewable energy.
However, the authors caution that these “positive tipping points” do not happen on their own. The report says a “concerted and coordinated action is usually needed to create the enabling conditions for triggering positive tipping points.”
For today’s Climate Classroom, Jeff Berardelli is interviewing Dr. Steve Smith, an author of the report and an expert on “positive climate tipping points.” You can read more on the comprehensive report here.
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