Climate, Weather, and Water: Powering Our Future

1. Poweringour future withweather, climate and water • A large part of mypresentationwilladdressExtremeevents • A few words on the meeting organizedyesterday (FIM) • Global warming : an overview (IPCC AR4).

2. 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 ?

3. 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 3) Warmingwill continue 2010 Carbon dioxide + 39 % Methane +150 % Nitrous oxide + 20% • 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

4. Temperature difference between 2010 /1970 (Hansen et al., 2011) Average global warming de 0.66 ° ; more than twice in the Arctic

5. 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

6. Our activities have little influence on the climate of the coming decade 1.8°C 1.1 - 2.9 B1 983 GtC 2.8°C 1.7 - 4.4 A1B 1499 GtC 3.4°C 2.0 - 5.4 A2 1862 GtC But the climate at the end of this century depends on our activities

7. Temperatures Winter Summer Précipitations • 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… • Numerous uncertainties : • emission scenarios • importance of global warming • regional characteristics, précipitation • clouds, aerosols • evolution of ice sheets • climatic surprises • ……..

8. Africa is particularly vulnerable Winter Summer

17. More droughts in some regions

18. Between 20 and 60 cm unti 2100, may be moreRisk 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

19. Have human activities already affected our climate? 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 Observations Natural causes (solar activity, volcanoes)

20. En