Presentation on theme: "Powering our future with weather, climate and water A large part of my presentation will address Extreme events A few words on the meeting organized yesterday."— Presentation transcript:
Powering our future with weather, climate and water A large part of my presentation will address Extreme events A few words on the meeting organized yesterday (FIM) Global warming : an overview (IPCC AR4).
Weather forecasts and hydrological information are a part of daily life in industrial countries but are largely absent from developing countries Development, climate and hydro-met services Health and disaster risk reduction Industry and Energy Agriculture and Water How to develop sustainable hydro-met services ?
1) Human activities are modifying the composition of the atmosphere in greenhouse gases (important and rapid) IPCC 2007 : we are certain of 2) Warming is uniquevocal Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations. Numerous uncertainties remain Carbon dioxide + 39 % Methane +150 % Nitrous oxide + 20% 3) Warming will continue 2010
Temperature difference between 2010 /1970 (Hansen et al., 2011) Average global warming de 0.66 ° ; more than twice in the Arctic
A1B is a typical « business asusual scenario » At the end of the century (2090 – 2099), the projected global warming is of 2.8°C (average value) Much of land areas warms by ~ 3°5 C ; Arctic warms about 7°C ; less if less emissions ; more if more emissions
Our activities have little influence on the climate of the coming decade B1 983 GtC A1B 1499 GtC A2 1862 GtC 2.8°C 1.7 - 4.4 But the climate at the end of this century depends on our activities 1.8°C 1.1 - 2.9 3.4°C 2.0 - 5.4
Numerous impacts : more frequent heatwaves increased risk of droughts in some regions increase risk of floods in other regions more intense precipitaion events risk of more intense cyclones sea-level rise, permafrost melting ocean acidification, ecosystems, health agriculture, tourism, infrastructures… Précipitations WinterSummer Temperatures Numerous uncertainties : emission scenarios importance of global warming regional characteristics, précipitation clouds, aerosols evolution of ice sheets climatic surprises ……..
Between 20 and 60 cm unti 2100, may be more Risk of a few meters in a few centuries Deltas World population should rapidly increase in coastal areas with increasing risks linked with sea-level rise
Natural causes (solar activity, volcanoes) Observations Anthropogenic activities Greenhouse gases and aérosols natural causes Most of the observed increase in global average temperature since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentration Have human activities already affected our climate?