Francisco J. Doblas-Reyes
ICREA Professor, Director of the Earth Sciences Department at the Barcelona Supercomputing Center
The Synthesis Report leaves us with shattering evidence of the need to address adaptation to climate change and mitigation of human-induced emissions together. It highlights the fact that climate change is already taking place and is expressing itself in all regions of the planet in different ways, as would be expected on a planet that has warmed by more than one degree since pre-industrial times. At the same time, it makes it clear that the solution remains in the hands of global society, since both the speed of warming and the level reached by the end of the century depend above all on emissions from now on.
In any case, and taking into account the trajectory for the rest of the century and beyond, since the impact of warming will continue to be present in some variables such as sea level for many centuries, it is clear that the impacts depend fundamentally on accumulated emissions and that the only way to limit them is to reduce those emissions as fast as possible and at the fastest rate that society is able to assimilate in a systemic transformation. Until that happens, impacts will continue to grow due to the increased frequency and intensity of extreme weather events. This is important not only for the most vulnerable societies, such as economies in transition, but also for environments such as ours because the standards by which society and the economy are governed have not taken into account a changing climate.
We still have much to know about the behaviour of the climate system, how it reacts to the increase of greenhouse gases in the atmosphere or how the impacts of changes in climate on society, the economy and ecosystems will manifest themselves. But the report's conclusions about what we know now leave no doubt that it is time to act, and to do so in a way that is fair to the most vulnerable and to future generations.