“With this declaration, we outline the scale of the threat of climate change, and we provide the best possible advice,” says Brian P. Schmidt, Nobel laureate and a spokesperson for the Mainau Declaration 2015 on Climate Change.

He continues that he feels a “moral bound duty as a scientist on an issue that has such lasting consequences.” Four Nobel Laureates met with Brian Schmidt on Thursday, one day before the signing of the declaration on Mainau island of Lake Constance on the last day of the 65th Lindau Nobel Laureate Meeting. These five scientists discussed this threat to mankind and possible steps and solutions: Steven Chu, former US Secretary of Energy, George Smoot, David Gross, Peter Doherty, and Schmidt, a Nobel Prize winning astrophysicist.

The declaration text itself states: “If left unchecked, our ever-increasing demand for food, water, and energy will eventually overwhelm the Earth’s ability to satisfy humanity’s needs, and will lead to wholesale human tragedy.”

Gross tells his fellow laureates and the attending journalists how he just visited Ladakh in the Himalayas: “These are fragile communities, they are very dependent on the rivers that spring from the Himalayan glaciers, and they are the ones that suffer first.” He points out that in the future, there might even be wars fought over water in several regions of the world. Doherty quotes from the Lancet Commission’s latest report: “They say that we may expect the breakdown of civil society in 21. century. And the poor on the planet are going to be the most affected, as always.” All Nobel Laureates discussing the declaration in Lindau on Thursday morning agree unanimously that there is overwhelming evidence that emissions of greenhouse gases cause global warming. “There might be some uncertainties left,” concedes Chu. “It’s like in the 1950s when people didn’t know what happened if you smoked one pack of cigarettes per day – but the lung cancer rate was rising so rapidly that something had to be done.” Nowadays we can calculate the cancer risk of smoking quite precisely. “But do we want to wait fifty years until we know what will happen with global warming?”, he asks. Chu adds: “You don’t wait until your house is on fire before you take out fire insurance.” Doherty gives another analogy: when the HI virus was first discovered, many people, even scientist, doubted its role in the AIDS epidemic. But once the virus’ life cycle was understood and could be disrupted with antiviral drugs, most denial dropped.     Doherty also defines the difference between denial and scepticism: “If you’re sceptic, you talk to other researchers, you look at the data. If you’re in denial, you simply reject everything that’s being published.” Steven Chu explains how the best data on climate change comes from satellites: they clearly show how glaciers are shrinking all over the world, from Greenland and the Arctic to the Himalaya, the Alps and some parts of Antarctica. “But there are people in Congress who don’t want to look at satellite pictures,” he remembers from his time in politics. “That’s what I call denial.” The Nobel Laureates agreed that politicians should act immediately to “lower the current and future greenhouse gas emissions”, as the declaration states. These politicians will meet at the 2015 UN Climate Change Conference in Paris, starting November 30, 2015. “It takes half a century to turn the boat,” states Chu. While it is true that newable energy technologies keep getting cheaper, this takes time. “At some point, the technology will be competitive.” Smoot adds: “You need infrastructure for that. This will also create jobs and give us a better infrastructure.” Doherty thinks that not only politicians need to reach results, but voters need to urge their leaders to act: “Politicians care about nothing except votes. So you have to convince the people who vote.” Schmidt replies that yes, voters could and should be informed about climate change, but that many politicians “will realise that they have a responsibility – it’s not only votes.” Altogether, the laureates are cautiously optimistic, for instance when they think about the US-China Joint Announcement on Climate Change last November. “It shows that we can move forward in the divide between developing and developed nations,” Smoot explained. This divide was one of the main obstacles in the past UN Climate Change Conferences in Copenhagen and Rio de Janeiro. The laureates believe that the global warming challenge can be met with a combination of politics and technology, Doherty: “We’ll solve this through policy and technological innovation – and the latter drives economy.”

Chu concludes: “I’m a technological optimist and political optimist. It is possible to find a solution, but we’re running against the clock,” because change is getting more urgent – and more expensive – all the time.

For all further information on the Mainau Declaration 2015 on Climate Change please visit Lindau-Nobel.org.