Our evolution has chosen a “fight or flight” instinct to deal with environmental change, so as the metaphor of the frog in boiling water, we tend to react too little and too late for a gradual change. means.
Climate change is often defined as global warming, with the effects of gradual changes caused by a steady rise in temperature; from heat waves to melting glaciers.
But we know from multidisciplinary scientific evidence – from geology, anthropology and archeology – that climate change is not gradual. Even in pre-human times, it is accidental, when it is not triggered by the acceleration of greenhouse gas emissions and warming.
There are parts of our planet’s carbon cycle, the ways in which the earth and biosphere store and release carbon, which can start suddenly in response to gradual warming. These are points of tension that could fundamentally overtake the planet and bring about a sudden non-linear change in the climate.
Game of Jenga
Think of it as a game of Jenga and the climate system of the planet as the tower. For generations, we’ve been slowly removing blocks. But at some point, we will remove an important block, such as the collapse of one of the major global ocean circulation systems, for example the Meridional Overturning Circuit (AMOC), which will cause all or part of the global climate system to collapse. . into a planetary crisis.
But even worse, it could cause runaway damage: Where the tipping points create a domino-like block, where the breaking of one induces the breaking of others, creating an unstable transition to a climate that is changing rapidly and rapidly.
One of the biggest waste points is the distribution of large methane. Methane is found in deep frozen storage within permafrost and at the bottom of the deepest oceans in the form of methane hydrates. But rising sea and air temperatures are starting to melt these methane sources.
This would release a powerful greenhouse gas into the atmosphere, 30 times more powerful than carbon dioxide as a global warming agent. This would significantly raise temperatures and drive us towards breaking other waste points.
This could include the acceleration of ice melting on the three major land-based ice sheets – Greenland, West Antarctica and the Wilkes Basin in East Antarctica. The collapse of the West Antarctic ice sheet is seen as a major source of tension, as its loss of global sea levels could rise by 3.3 meters with significant regional changes.
In addition, we would be on the unstable path to full melting of land ice, causing sea levels to rise by up to 30 meters, about two meters per century, or perhaps faster. Just take a look at the elevated beaches around the world, at the last high level of the global sea level, at the end of the Pleistocene period about 120,0000 years ago, to see evidence of such a warm world, which was just 2 ° C warmer than today.
Cutting off circulation
In addition to destroying lowland and coastal areas around the world, the melting of polar ice could put off another point: disability for the AMOC.
This circulatory system drives a northerly flow of warm, salty water on the upper reaches of the ocean from the tropics to the northeast Atlantic region, and a southerly flow of deep cold water. in the bay.
The ocean conveyor belt is heavily influenced by climate, seasonal cycles and temperatures in western and northern Europe. It makes the region warmer than other areas of the same width.
However, the melting of ice from the Greenland ice sheet could threaten the AMOC system. It attenuated sea salt water in the North Atlantic, making the water lighter and more or less able to sink. This would slow down the engine that controls the circulation of this ocean.
Recent research shows that the AMOC has already weakened by about 15% since the mid-20th century. If this continues, it could have a significant impact on the climate of the northern hemisphere, but especially in Europe. This may stop arable farming in the UK, for example.
It could also reduce rainfall over the Amazon basin, affect the monsoon systems in Asia and, by bringing warm waters into the South Sea, further ice imbalance in Antarctica and acceleration global sea level rise.
The Atlantic Meridional Tide has a profound effect on the climate. Praetorius (2018)
Is it time to name a climate crisis?
To what extent, and at what increase in global temperature, will these tensile points be reached? No one is entirely sure. It may take centuries, thousands of years, or it may be close.
But as COVID-19 taught us, we need to prepare for what was expected. We were aware of the risk for pandemic. We also knew we were not prepared enough. But we did not act in a meaningful way. Fortunately, we were able to quickly develop vaccines to combat COVID-19. But there is no vaccine for climate change once we are past these stress points.
We need to work now on our climate. Action like these stress points is forthcoming. And stop thinking of climate change as a slow, long-term threat that will allow us to kick the problem down the road and allow future generations to tackle it. We need to take immediate action to reduce global warming and deliver on our Paris Agreement commitments, and build resilience with these tensions in mind.
We need to plan now to mitigate greenhouse gas emissions, but we also need to plan for the effects, such as the ability to feed everyone on the planet, develop plans to manage flood risk, as well as managing the social and geopolitical influences of people. migrants resulting from combat or flight decisions.
Breaking these stress points would be cataclysmic and could be far more devastating than COVID-19. Some may not like to hear these messages, or regard them as true science fiction. But if it involves a sense of urgency to make us respond to climate change as we have to the pandemic, we need to talk more about what has happened before and it will happen again.
Otherwise we will continue to play Jenga with our planet. And in the end, there will be only one loser – us.
Posted by permission of the World Economic Forum.