Are We Past the Point of No Return for Climate Change?
Written by Kari West
When discussing climate change and possible solutions, people often question whether or not it’s already too late to take action. There is talk of the so-called “point of no return”, a threshold which, once crossed, will result in runaway heating that we can do nothing to stop. Have we already sealed our global heating fate? The short answer is no, it’s not too late.
The idea of a “point of no return” or tipping point that will guarantee all forms of climate-related destruction does not exist. Rather, there are several different tipping points that will kick off positive feedback loops for certain climate related changes such as melting ice or drastic changes in the biosphere. This means that while a specific outcome is not necessarily guaranteed after reaching its tipping point, the process that gets us closer and closer to the outcome is self-sustaining. Take melting ice for example: ice helps to reflect the sun’s rays away from earth instead of absorbing them. When ice begins to melt, it exposes more water or land. Water and land absorb rather than reflect radiation from the sun, warming the Earth and causing more ice to melt. If enough ice melts, there is a tipping point at which the melting is substantial enough to cause further melting until little, if any, ice is left. Once a tipping point like this is reached, human intervention will be necessary to stop the positive feedback loop.
To assess how damaging these tipping points are, we can look to recent history. The Earth has already reached some tipping points, and their results can be measured. Many scientists have concluded from data spanning the last several years that high temperatures in oceans passed the “point of no return” back in 2014. They found that extreme temperatures that a century ago used to only occur 2 percent of the time, now occur around 50 percent of the time. This 50 percent of the time trend began in 2014, suggesting that we have crossed the threshold into a new “normal” for global ocean temperatures. Additionally, certain parts of the ocean had already reached these levels of heating, the South Atlantic, for example, having crossed its “point of no return” way back in 1998. These results reflect the fact that climate change does not affect everything equally. This is something to take into account as politicians decide how much climate action is necessary to combat current impacts. Some parts of the globe have already been dealing with extreme climate impacts for decades. So while some tipping points may not immediately affect the way we live here in California, they can exacerbate the consequences for those who experience the most impacts. Did reaching this tipping point cause the world to go up in flames and become uninhabitable? No, but it did have devastating impacts, the extent of which we have yet to experience. Marine life, for example, is heavily affected by changing water temperatures, and that consequence will reach us eventually.
While different climate impacts may each have their own specific tipping points, they are not necessarily independent of each other. Some research suggests that tipping points can interact with each other. This means that if we reach one tipping point, it may increase the likelihood that another will be reached, and so on as we reach more and more thresholds that activate positive feedback loops. As global temperature increases, we are more and more likely to activate these positive feedback loops. Then, both rising temperature and the activation of the last feedback loop may help to activate the next one. Given this pattern, it would be best to limit the number of tipping points we reach to as few as possible.
The idea that we are past the point of being able to intervene and reduce the effects of climate change is false. It is in our best interest not to activate the positive feedback loops that will accelerate climate change impacts, but it won’t be the end of the world if we do get to that point. It will never be too late, but the longer we wait, the worse the consequences will become.
References:
https://www.air-worldwide.com/blog/posts/2019/4/arctic-amplification-a-very-bad-positive-feedback-loop/
https://www.theguardian.com/environment/2022/feb/01/extreme-heat-oceans-passed-point-of-no-return-high-temperatures-wildlife-seas
https://iopscience.iop.org/article/10.1088/1748-9326/ac3955