Skip to main content

Climate Expert Hans Joachim Schellnhuber

German climate expert Hans Joachim Schellnhuber is fighting for a 1.5-degree target.


Climate is right back at the top of the agenda in 2015. First the G7 agreed on a binding 2- degree target for limiting global warming at its June summit in Germany, then Pope Francis published his Laudato si’ encyclical which saw a Papal circular focus for the first time on the environment. UNESCO is now staging a climate conference in Paris – the biggest meeting of climate researchers in 2015 – in preparation for December’s important United Nations Climate Change Conference in Paris (COP21). Researchers are urging for global warming to be limited to a maximum of 2 degrees – this is equivalent to the pre-industrialization level.

1.5 degrees is possible

Hans Joachim Schellnhuber from Germany is one of the world’s leading climate experts. The director of the Potsdam Institute for Climate Impact Research (PIK), he was one of the first to call for lasting solutions to the problem of climate change and to commit himself to limiting global warming.

In cooperation with researchers from the International Institute for Applied Systems Analysis (IIASA) in Vienna, his institute published a study in May 2015 showing that it would be possible to limit global warming to less than 1.5 degrees Celsius by the year 2100. The 1.5-degree target is regarded as safer than the 2-degree line, and is supported by more than one hundred countries. That said, the project is ambitious: “In the 1.5-degree target scenarios, the remaining carbon emissions budget is nearly cut in half as compared with the 2-degree scenarios,” says the PIK’s Gunnar Luderer, one of the authors of the study. Accordingly, worldwide carbon neutrality would need to be achieved ten to twenty years earlier than in the 2-degree scenarios. In addition, carbon dioxide would have to be removed from the atmosphere.

Science is painting an ever clearer picture of the consequences of climate change: from sea level rises and extreme weather phenomena, damage to crops and the destruction of ecosystems to the potential for social unrest. Schellnhuber has developed models which make it easier to understand climate change. He advises the German government on questions of environmental change and is a longstanding member of the Intergovernmental Panel on Climate Change (IPCC), which was awarded the Nobel Peace Prize in 2007. He accompanied Pope Francis when the encyclical was presented in June, and will discuss “Reflections on Collective Action and Transforming Solutions” at the UNESCO climate conference in July.

UNESCO climate conference on “Our Common Future under Climate Change”  from 7 to 10 July 2015 in Paris