Our evolution has chosen the instinct “fight or flight” to deal with environmental change, and rather like the metaphor of the frog in boiling water, we tend to respond too little and too late to gradual changes.
Climate change is often described as global warming, with the implication of gradual changes caused by a constant increase 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 if not forced by a human-induced acceleration of greenhouse gas emissions and warming.
There are parts of the carbon cycle of our planet, the ways in which the earth and the biosphere store and release carbon, which can suddenly arise as a result of gradual warming. These are tipping points that could fundamentally disrupt the planet and cause sudden, non-linear climate change.
A game of Jenga
Think of it as a game of Jenga and the climate system of the planet as the tower. For generations, we have been slowly removing blocks. But at some point we will remove a core block, such as the collapse of one of the largest global ocean circulation systems, for example the Atlantic Meridional Overturning Circulation (AMOC), which will drop all or part of the global climate system. in a planetary emergency.
But even worse, it can cause runaway damage: where the tipping points form a domino-like cascade, where the offense causes others, causing an unstoppable shift to a radical and rapidly changing climate.
One of the most important tilting points is the release of methane. Methane can be found in deep-freeze storage in permafrost 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 stocks.
It will release a powerful greenhouse gas into the atmosphere, 30 times stronger than carbon dioxide than a global warming agent. This will cause the temperatures to rise drastically and lead us to other tipping points.
This could include the acceleration of ice thawing on all three major ice sheets on earth – Greenland, West Antarctica and the Wilkes basin in East Antarctica. The possible collapse of the West Antarctic ice sheet is considered an important tipping point, as the loss could eventually increase world sea level by 3.3 meters, with significant regional variations.
More so, we would be on the irreversible path to the complete melting of ice on land, which would raise sea levels by up to 30 meters, about two meters per century, or perhaps faster. Just look at the elevated beaches around the world, at the last high state of world sea level, at the end of the Pleistocene period about 120,0000 years ago, to see the evidence of such a warm world, which is only 2 ° C was warmer than the present.
To cut off circulation
In addition to devastating low-lying and coastal areas around the world, melting ice can also cause another tipping point: a disability for the AMOC.
This circulation system drives a northward stream of warm, salt water across the upper layers of the ocean from the tropics into the northeastern Atlantic region, and a southward stream of cold water deep into the ocean.
The ocean conveyor belt has a major impact on the climate, seasonal cycles and temperature in Western and Northern Europe. This means that the region is warmer than other areas with a similar latitude.
But the melting of ice from the Greenland ice can threaten the AMOC system. This will dilute the salt water in the North Atlantic Ocean, making the water lighter and less able to sink. This will slow down the engine circulating this ocean.
Recent research suggests that the AMOC has weakened by about 15% since the middle of the 20th century. If it continues, it could have a major impact on the climate of the northern hemisphere, but especially Europe. It could even lead to the cessation of arable farming in the UK, for example.
It could also reduce rainfall across the Amazon Basin, affect the monsoon systems in Asia, and, by bringing warm waters into the Southern Ocean, further destabilize ice in Antarctica and accelerate the world’s sea level rise.
The Atlantic Meridional Reversal Circulation has a major impact on the climate. Praetorius (2018)
Is it time to declare a climate crisis?
At what stage and with what rise in world temperatures will these tipping points be reached? No one is completely sure. It could take centuries, millennia, or it could be at hand.
But as COVID-19 has taught us, we need to prepare for the expected. We were aware of the risk of a pandemic. We also knew we were not adequately prepared. But we did not act meaningfully. Fortunately, we were able to quickly detect the production of vaccines to combat COVID-19. But there is no vaccine for climate change once we have passed these tipping points.
We must now respond to our climate. Act like these tipping points are at hand. And stop thinking of climate change as a long-term threat that enables us to kick the problem off the road and deal with future generations. We must act immediately to reduce global warming and meet our commitments to the Paris Agreement and build resilience with a view to these tipping points.
We must now plan to reduce greenhouse gas emissions, but we must also plan the consequences, such as the ability to feed everyone on the planet, develop plans to manage the flood risk, as well as the social and geopolitical consequences of human migrations. which will result from combat or flight decisions.
Violation of these tipping points would be cataclysmic and potentially much more devastating than COVID-19. Some do not like to hear these messages, or consider it a science fiction. But if it has a sense of urgency to make us respond to climate change as we did to the pandemic, we need to talk more about what has happened before and what will happen again.
Otherwise we will continue to play Jenga with our planet. And in the end, there will be only one loser – us.
Replaced with permission from the World Economic Forum.