On the same topic
This is a huge new job more than five years just to complete the Intergovernmental Panel on Climate Change (IPCC). Under the auspices of the United Nations, he revealed on Friday in Stockholm, the first conclusions of the fifth report, a crucial step on the state of scientific knowledge. It points more than ever the role of human activity in increasing both average temperatures than in extreme weather events. Valérie Masson-Delmotte is one of 800 scientists mobilized on the subject. This climatologist at the Laboratory of Climate and Environment * oversaw the chapter on climate change in the past. She explains the challenges of meeting between science and policy as well as the latest findings on climate.
are meeting between scientists and representatives of 110 countries since Monday in Stockholm. How is your work there consisted recent days
The challenge was to get around the table to approve, word by word, “the summary for policy makers” (link in English) by the assembly of delegates from different countries. This summary of some thirty pages is sleek figures (note: graphs, maps, etc..), But still technical. It is essential to go to. Each word having an impact, they must be chosen with precision. The document will then serve as a common scientific basis between countries (to help policy decision, Ed.)
not there he was not a temptation for politicians to influence the outcome of scientific research
This phase does give rise to some interesting discussions, as the political agenda of each country is not the same. This is not censorship, this is primarily a work of decoding: what they say is well understood by politicians, and vice versa? The consensus on this summary does not therefore our results, but how to say things. While it is true that some would mitigate the finding highlight the uncertainty, while others would put well under the carpet aspects reminiscent of the complexity of the climate system.
on site, I was struck by an express very multipolar world. We scientists working on the climate of the planet, but they represent the human world. The fact that the document is approved by such diverse countries as Germany, Saudi Arabia, Brazil and China is a real asset to the discussions between States.
What are the main lines, which is confirmed, which is new compared to previous reports
The 2007 report already affirmed the role of human activities on climate and rising temperatures. Today, this situation is much thinner, clear and precise. Across decades, whether on rising sea levels, melting ice and glaciers, warming oceans deep or extreme events, the man is the main cause of all these changes unequivocal.
On the evolution of trajectories temperatures, several scenarios are still possible by 2100, depending on the atmospheric composition. Two important numbers to remember are: from + 2 ° C in the case of large declines in our greenhouse gas at 4 ° C in case of continuation of current releases. As for the rise in sea level, it is currently 3 mm per year, after growing 20 cm in the twentieth century. In the highest scenarios, the total rise could reach the end of the century a meter compared to the preindustrial era.
In the previous report, errors were committed, including the melting of Himalayan glaciers. The method has she been strengthened to prevent this?
On a final report of 1000 pages, of course, we are never immune to error. The review process has been revised, publishers must verify proper consideration of comments by validating or rejecting. It is also easier to make adjustments.
Have you identified more clearly the origin of the so-called “climate pause”
There has slowing of global warming over the past fifteen years. Several volcanic eruptions and a decrease in solar activity played a role in the slowdown of rising temperatures, but at the margin. The main cause is to be found in the oceans, where the heat builds up in depth.
Specifically, we disrupt the climate by increasing the greenhouse effect, by trapping rather than the energy back to space. You should know that 93% of this energy is stored and trapped by warming sea water, 3% warms the soil, 3% is consumed in the melting of ice and 1% only, is stored through the atmospheric warming. So you see a very small variation of the energy exchange between ocean and atmosphere can play an important role in a decade to the next. We have no control over the mechanism of internal climate variability. But when we look at the next thirty years, all the scenarios show an atmospheric warming.
If our development patterns do not change, the worst is still to be feared, but rather the day after tomorrow
disturbances related to greenhouse gas emissions have a long life, around the millennium, as goes the climate response. This is an issue that we will bequeath, from one generation to another. The climate issue is universal, because it relates to all the inhabitants of the planet.
* Joint Research Unit involving the CNRS, CEA and Versailles Saint-Quentin University.
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