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 of2) 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

B1983 GtC

A1B 1499 GtC

A21862 GtC

2.8°C1.7 - 4.4

But the climate at the end of this century depends on our activities

1.8°C1.1 - 2.9

3.4°C2.0 - 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

Winter Summer

Temperatures

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

Winter Summer

Africa is particularly vulnerable

More droughts in some regions

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

Natural causes(solar activity, volcanoes)

Observations

Anthropogenic activitiesGreenhouse 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?

En