Why we need the next-to-impossible 1.5°C temperature target

Simon Donner is an Associate Professor of Climatology at the University of British Columbia. For the past decade, he has researched climate change impacts and the adaptation challenges facing the Pacific island countries.

The agreement signed at the United Nations climate summit in Paris has been hailed as historic, ground-breaking, and unprecedented.

At the same time, the targets are so ambitious that many climate analysts are rolling their eyes. The agreement aims to limit warming to “well below” 2°C above pre-industrial levels, and recognizes that avoiding 1.5°C of warming “would significantly reduce the risks and impacts of climate change.”

The emissions reduction commitments made by the participating countries are not close to sufficient to achieve these targets. Carbon budget analyses show it will be next to impossible to avoid the 1.5°C limit without “negative emissions” – sucking carbon dioxide out of the air, using technologies that are unproven or not yet in existence. 

It is therefore understandable that Oliver Geden of the German Institute for International and Security Affairs would argue in his article, “Paris climate deal: the trouble with targetism,” that the temperature targets in the agreement are the height of hypocrisy. 

Yet Mr. Gedden and other critics of the Paris Agreement are missing the point of the climate negotiations. The issue facing international negotiators is not the statistical odds of staying within stated temperature limits. The issue is what happens if we do not.

After all, this is a global climate agreement. And to many countries, passing those temperature limits could be a disaster.

The temperature targets were included in the agreement out of respect for developing countries and small island states like the Republic of Kiribati, where I have conducted climate research over the past decade. In particular, the lower 1.5°C target is a signal to these countries that the world recognizes the existential threat that comes with more warming.

There is no scientifically definable “safe” amount of climate change. Science can provide us with a guide to the impacts of different levels of warming. The amount of warming we deem as “safe,” however, depends on our values and our perception of risk.

The 2°C target was informed by science, but it was chosen by developed countries – the same countries that are historically most responsible for climate change.

If you live in a small island nation in the tropics, more than 1.5°C of global warming certainly seems dangerous. With more than 1 meter of sea-level rise, around 90% of countries like Tuvalu, the Marshall Islands, and Kiribati could become so prone to flooding as to be uninhabitable. While there’s large uncertainty about the rate of future sea-level rise, evidence from the distant past suggests that every 1°C of warming will eventually cause 2.3 meters of sea-level rise.

There’s even greater concern among larger countries like Fiji about coral reefs, a key source of food, income, and coastal protection in tropical countries. The world’s coral reefs are already in trouble due to warming and acidifying ocean waters. Research led by my colleague Dr. Katja Frieler shows that if warming can be kept to less than 1.5°C, two-thirds of the world’s coral reefs could be spared from serious degradation this century. With 2°C or more of warming, reefs covered with living corals could become an artifact of history.

The critics are correct in arguing that the world is unlikely to avoid 1.5°C of warming, or even 2°C of warming. Yet to dismiss the targets entirely is to dismiss the needs of countries that are full members of the international climate negotiations.

By agreeing on the temperature limits, we are officially recognizing the scientific evidence that harm will come with more warming. This helps ensure that countries like Kiribati which are most at risk will receive the needed international assistance, a key tenet of international climate policy since the creation of the U.N. Framework Convention on Climate Change in 1992. Though they have not received much attention in the international media, the adaptation, capacity-building, and finance sections are as central to the Paris climate agreement as the sections on emissions and temperature targets.

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Posted by Guest Author on Wednesday, 30 December, 2015

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