Climate challenges

Jean Jouzel was the guest of honor at HydroGaïa 2016. On the future of our planet's climate, the Nobel Prize winner takes an uncompromising look at the situation. " Stabilize the greenhouse effect if we don't want to head for catastrophe: it's a simple statement of common sense," explains Jean Jouzel.

Credit: Lucie Campenas

For the Nobel Prize winner, the situation is serious. But he believes that politicians are now taking seriously a scientific community that has been warning them for over 30 years about the dangers of global warming.

Short deadline

First observation: "globalwarming is unequivocal and unprecedented. It is largely due, estimated at 95%, to human activities". The main culprits are greenhouse gases. Stabilizing the greenhouse effect means reducing emissions. If we do nothing, we can expect "a warming of 4 to 5 degrees Celsius before 2100″.
A sudden, unprecedented and extremely worrying rise in temperature, especially as it could continue to increase... "A frightening prospect: we're moving into another world" comments the climatologist. A danger in the short term: "it doesn't threaten future generations, but rather the young people of today", he adds.


Reversing the trend? Impossible. When it comes to the climate, there's no going back... and we're paying the price for every indecision we've made in the past. That's why it's so important to start behaving virtuously today. In concrete terms, this means "rapidly and significantly divesting from the fossil fuel sector".
" Global warming is here, it's inevitable, it's irreversible," insists Jean Jouzel. The only conceivable objective is to keep it within reasonable limits in order to adapt to it. Keeping the average rise in global temperature below 2 degrees by the end of the century: this is one of the main points of the agreement reached at the Paris climate conference (COP21).


If we want to stay below 2 degrees, we only have about twenty years of fossil fuel use left, at the current rate,"comments Jean Jouzel, "a real challenge! And if the terms of the Paris conference remain "far from the objective", the climatologist is nonetheless pleased with this "universal agreement" signed by the 195 countries present.
Next step: COP 22, to be held in Marrakech from November 7 to 18, 2016. After the Paris agreements, this meeting is expected to be a "COP of action"."We have to get there right away! It's technically possible, and for the younger generations the challenge is exciting: to change the world, rather than continue on the same trajectory." A revolution at low cost, assures the climatologist: "staying below 2 degrees would mean reducing GDP by about a year every 30years. It's not suicidal; it's just another form of development", he concludes.

If nothing is done...

With average temperatures set to rise by 4 to 5°C, serious consequences can be expected in the Mediterranean region and around the world...

  • ocean acidification: the oceans are twice as acidic as they were at the beginning of the last century, with a direct threat to fish and coral reefs;
  • climate extremes": droughts, floods, heat waves, cyclones... In our regions, an increase in extreme events of the Cevennes type is to be expected;
  • risks for populations: climate refugees, dwindling water resources, food shortages, but also security problems: global warming is contributing to political instability in many regions;
  • environmental problems: loss of biodiversity, pollution, health, etc;
  • irreversible phenomena: rising sea levels, for example. On our coasts, it could reach almost 1 metre in some areas: a serious threat for low-lying regions such as the Camargue.

Jean Jouzel is one of the world's best-known climatologists and glaciologists, the recipient of numerous awards: CNRS Gold Medal in 2002 with Claude Lorius; Nobel Peace Prize in 2007 with the IPCC (Intergovernmental Panel on Climate Change) and Al Gore; Vetlesen Prize in February 2012.