Our evolution has selected the instinct to “fight or run” to cope with environmental change, so rather than the metaphor of the boiling water frog, we tend to react too little and too late to gradual change.
Climate change is often described as global warming, with the implication of gradual changes caused by a steady rise in temperatures; from heat waves to melting glaciers.
But we know from multidisciplinary scientific evidence – from geology, anthropology and archeology – that climate change is not incremental. Even in pre-human times, it is episodic, when it is not forced by a human-induced acceleration of greenhouse gas emissions and heating.
There are parts of our planet’s carbon cycle, the ways in which the earth and biosphere store and release carbon, which could suddenly trigger in response to gradual warming. These are high points that, once passed, could fundamentally disrupt the planet and could produce sudden and nonlinear changes in the climate.
A game of Jenga
Think of it as a Jenga game and the planet’s climate as a tower. For generations, we have slowly removed the blocks. But at some point, we will remove an essential block, such as the collapse of one of the world’s most important ocean circulation systems, for example, the Atlantic South Oversurning Circulation (AMOC), which will cause the entire system to collapse or part of it. in a planetary emergency.
But even worse, it could cause runaway damage: if the peaks form a domino-type waterfall, if the violation of one triggers violations of others, creating an unstoppable change in a climate that changes radically and rapidly .
One of the most troubling tipping points is the mass release of methane. Methane can be found in permafrost frost deposits and at the bottom of the deepest oceans in the form of methane hydrates. But rising sea and air temperatures are beginning to thaw these methane deposits.
This would release a strong greenhouse gas into the atmosphere, 30 times stronger than carbon dioxide as a global warming agent. This would drastically raise temperatures and rush us to break other tipping points.
This could include accelerating ice thawing on all three major ice sheets in the world – Greenland, West Antarctica and the Wilkes Basin in East Antarctica. The potential collapse of the ice sheet in western Antarctica is seen as a key point, as its loss could eventually increase global sea level by 3.3 meters, with significant regional variations.
Moreover, we would be on the irreversible path to the total melting of ice on land, causing sea levels to rise by up to 30 meters, at a rate of about two meters per century, or maybe faster. Just look at the high beaches around the world, at the last high level of global sea level, at the end of the Pleistocene period about 120.0000 years ago, to see the evidence of such a warm world, which was just 2 ° C warmer than today.
Cutting traffic
In addition to devastating low and coastal areas around the world, melting polar ice could trigger another tipping point: an invalidation of the AMOC.
This circulation system leads a northward flow of warm and salty water on the upper layers of the ocean from the tropics to the northeastern Atlantic region and a southward flow of cold water deep into the ocean.
The ocean conveyor belt has a major effect on the climate, seasonal cycles and temperature in Western and Northern Europe. It means that the region is warmer than other areas with similar latitude.
But melting ice in the Greenland ice cap could threaten the AMOC system. It would dilute the salt water of the North Atlantic, making the water lighter and less able or unable to sink. This would slow down the engine that drives this ocean circulation.
Recent research suggests that AMOC has already weakened by about 15% since the middle of the twentieth century. If this continues, it could have a major impact on the climate of the northern hemisphere, but especially of Europe. It can even lead to the cessation of arable agriculture in the UK, for example.
It can also reduce precipitation in the Amazon Basin, affect monsoon systems in Asia, and by bringing warm water into the Southern Ocean, further destabilize Antarctic ice and accelerate global sea level rise.
The circulation of the southern Atlantic overturn has a major effect on the climate. Praetorius (2018)
Is it time to declare a climate emergency?
At what stage and in what increase in global temperatures will these tipping points be reached? No one is completely sure. It can last for centuries, millennia or it can be imminent.
But as COVID-19 has taught us, we must prepare for what we expect. We were aware of the risk of a pandemic. I also knew we weren’t prepared enough. But I did not act in a significant way. Fortunately, we were able to quickly track the production of vaccines to combat COVID-19. But there is no vaccine for climate change after we have passed these tipping points.
We must act now according to our climate. Act as if these peaks are imminent. And stop thinking of climate change as a slow, long-term threat that allows us to throw the problem on the road and let future generations take care of it. We must take immediate action to reduce global warming and to meet our commitments to the Paris Agreement and to build resilience in the light of these critical points.
We need to plan now to mitigate greenhouse gas emissions, but we also need to plan for impacts, such as the ability to feed everyone on the planet, develop flood risk management plans, and manage impacts. social and geopolitical aspects of man. migrations that will be a consequence of fighting or flight decisions.
Violation of these peaks would be cataclysmic and could be far more devastating than COVID-19. Some may not like hearing these messages or consider them to be in the science fiction field. But if it injects us with a sense of urgency to make us respond to climate change as we did in the pandemic, then we need to talk more about what happened before and will happen again.
Otherwise we will continue to play Jenga with our planet. And finally, there will be only one loser – us.
Reposted with the permission of the World Economic Forum.