What is half a degree? In the grand scheme of things, it may not sound like much. In this case, it could have a dramatic impact. On October 8, the United Nations’ International Panel on Climate Change (UNIPCC) released a report exploring the impacts of a 0.5°C (0.9°F) difference in global temperature. More specifically, they looked at the difference between a 2°C (3.6°F) rise in global temperatures compared to a 1.5°C (2.7°F) increase. The differences are colossal.
At an increase of 1.5°C, the UNIPCC expects a mere 1% of coral to survive. At an increase of 2°C, this percentage is multiplied by ten. What’s more, this figure does not even capture the impact on broader marine ecosystems, in which corals play a vital role. 25% of all marine species are supported by coral. The consequences of corals going extinct would be devastating.
Unsurprisingly, the Arctic will also be gravely affected by temperatures rising, making ice-free summers in the Arctic a much more prevalent occurrence. The exact frequency will be determined by our ability to limit the temperature increase. Reaching a 2°C increase would cause this phenomenon to happen every 10 years, as opposed to every 100 years, if we keep it under 1.5°C.
The destruction of this ecosystem is dramatic in and of itself. Many endangered species would be further threatened. Moreover, the Arctic is distinct from other ecosystems on the planet. It plays a vital role in global climate regulation via the cooling effect it creates in both sea and air currents. Its destruction would cause climate deregulation, intensifying and increasing the frequency of floods, droughts, and heat waves more so than ever. With the volume of Arctic sea ice decreased by 70% compared to 40 years ago, we have already caused far-reaching damage.
The direct impact of melting Arctic icebergs on humans is a rise in sea levels. This would have devastating impacts on our coastal cities; Shanghai, for example, would be flooded and entirely submerged with a 3°C temperature increase. The half a degree difference would impact double the amount of people simply from water stress alone. Furthermore, an estimated 420 million people more would be exposed to extreme heat waves in the case of a 2°C increase compared to the 1.5°C.
Johan Rockström, co-author of the “Hothouse Earth” report published in August 2018, explains that “[The UNIPCC] report is really important. It has a scientific robustness that shows 1.5°C is not just a political concession. There is a growing recognition that 2°C is dangerous.”
The “Hothouse Earth” report explores the impact of a 2°C increase. One of the possible outcomes put forth is the establishment of a ‘hothouse Earth’ climate. Here, global temperatures stabilize at 4°C or 5°C above pre-industrial levels and sea levels are 10 metres to 60 metres higher than they are today. The authors argue that this will happen through “feedbacks” – Earth system processes that may be triggered by global warming. A 2°C increase might already be too much, as it may prompt these processes, taking global warming beyond human control and past the point of no return. “Places on Earth will become uninhabitable if ‘hothouse Earth’ becomes a reality,” says Rockström.
The UNIPCC and “Hothouse Earth” reports both stress the urgency of taking action. We have already reached a 1°C increase compared to pre-industrial temperatures, and with the current levels of commitment, we are headed towards a 3°C rise in temperatures by 2100. Any escalation past the 2°C increase explored in these reports becomes increasingly dangerous.
To prevent any further increase, both reports underscore the importance of cutting our carbon dioxide and greenhouse gas emissions as fast as possible. Will Steffen, the lead author of the “Hothouse Earth” report, stresses the importance of doing so; he explains that feedbacks will come into effect and cause temperatures to rise even without any additional emissions.
We need to reduce our greenhouse gas emissions much faster than initially believed– we have less than 12 years to make an impact. This means imposing much stricter and much lower limits than the ones provided at the Paris Agreement, ratified in 2016. It may also include exploring faster ways of removing carbon dioxide from the atmosphere. This can include the protection and expansion of forests and vegetation, as well as the development of carbon capture and storage techniques.
It can be done, but governments need to push forth policies and take a hard stance on the matter. As Jim Skea, a co-chair of the working group on mitigation for the UNIPCC report, said, “We show it can be done within the laws of physics and chemistry. Then the final tick box is political will. We cannot answer that. Only our audience can– and that is the governments that receive it.”
Hans Joachim Schellnhuber, another co-author of the “Hothouse Earth” report, criticized political leaders’ statements concerning what is achievable, blaming their lack of motivation on their interest in short-term goals, for which they can take credit.
In Amsterdam, while the appeals court did not agree with this explanation, it did support the argument that more could, and should, be done in the way of limiting greenhouse gas emissions. On 0ctober 9, the court upheld a previous ruling demanding the Dutch government to cut greenhouse gas emissions by 25% before 2020. The main argument for appeal was the fact that a court was deciding on government policy. This claim was dismissed on the basis that courts have to hold the government accountable to both local and international laws and regulations.
The Dutch court ruling is a great example of what needs to be done. If politicians are going to be complacent, it is up to other areas of society to step up and show their support for environmental issues. Debra Roberts, a co-chair of the working group in the UNIPCC report, referred to the report as “the largest clarion bell from the science community,” and hopes that “it mobilizes people and dents the mood of complacency.”
This just might be the case within the McGill community. This Monday October 22, Divest McGill organized a rally for divestment, demanding the university to stop supporting the fossil fuel industry. Schellnhuber commented, “I think that in the future people will look back on 2018 as the year when climate reality hit. This is the moment when people start to realize that global warming is not a problem for future generations, but for us now.”
There is still some hope left within the scientific community, linked to the recent and recurring heatwaves. With abnormally hot temperatures expected to last until at least 2022, citizens across the globe will experience the impact of global warming for themselves. A silver lining lies in the hope that this first-hand experience will spark a desire for change and push people to action. With a bit of luck, it won’t be too late.