Climate Change: an Introduction ecbi Workshops 2007 Claire N Parker Environmental Policy Consultant european capacity building initiative initiative européenne de renforcement des capacités ecbi for sustained capacity building in support of international climate change negotiations pour un renforcement durable des capacités en appui aux négociations internationales sur les changements climatiques

The greenhouse effect in the atmosphere

Natural and man-made carbon cycles OCEAN LAND ATMOSPHERE Annual transfers,natural and human-made (GtC) 3.3 Source: IPCC

CO 2 is major contributor to global warming Current emissions, effect over next 100 years Methane 24% Carbon dioxide 63% Nitrous oxide 10% Others 3%

Sources of Greenhouse Gases CO 2 from fossil fuel use (mainly power generation, transport) and land use change (e.g. deforestation) CH 4 (methane) and NO 2 (nitrous oxide) primarily from agriculture

Stages in predicting climate change CONCENTRATIONS CO 2, methane, etc. HEATING EFFECT ‘Climate Forcing’. IMPACTS Flooding, food supply, etc. Scenarios from population, energy, economics models Carbon cycle and chemistry models Gas properties Coupled climate models Impacts models CLIMATE CHANGE Temp, rain, sea level, etc. EMISSIONS feedbacks

The climate system

Strong global warming observed since 1975

IPCC’s AR Warming is unequivocal… now clearly evident in many aspects of the climate system

Signs of climate change Earth surface has warmed by 0.74  C over last century Sea levels rose 20cm last century Glaciers, snow cover and sea ice all declining More heat-waves, droughts and extreme rainfalls More intense cyclones

Carbon dioxide in the atmosphere: rapid rise due to human activities

CO 2 from fossil-fuel burning: rapid rise since 1950 Source: CDIAC, ORNL

Other Greenhouse gases Similar patterns are observed for methane (CH 4 ) and nitrous oxide (NO 2 )

AR4: high confidence in radiative forcing data Anthropogeni c is > 10 times that of solar since 1750

AR4: models are getting better Models are used to simulate the warming of the last 150 years Their results correlate with anthropogenic + natural warming Natural causes can’t explain what has happened.

AR4: observed vs. modelled global climate change

What do models predict? AR4: There is now higher confidence in projected patterns of warming, and other regional-scale features, including changes in wind patterns, precipitation and some aspects of extreme events and changes in ice cover

This century global temperature likely to be between 1.8 and 4 C above today’s

A further warming of about 0.6  C likely from past emissions alone Scale of warming depends on emissions: Low scenario 1.1 – 2.9 C High scenario 2.4 – 6.4 C

Geographical patterns of warming Warming expected to be greatest over land and at high northern latitudes

Sea levels will rise by 18 to 59 cm by Additional cm or more may come from Greenland and Antarctic ice sheets Snow cover, glaciers and sea ice will continue to decline Rainfall and wind patterns will change Extreme events (rainfall and droughts) more frequent Tropical cyclones more intense Meridional Overturning Circulation in N Atlantic likely to slow down by 25% Other changes in climate will continue

The Atlantic Ocean’s Circulation System

Changes will continue for centuries, even if GHG concentrations were to be stabilised by 2100

Emissions to 2000, and IPCC projections to 2100

Towards dangerous levels

Past and projected CO 2 emissions from fossil fuel burning IEA World Energy Outlook 2004

References & Acknowledgements Climate Change and The Greenhouse Effect, A briefing from the Hadley Centre, Dec IPCC, Climate Change 2001 Synthesis Report of the Third Assessment Report IPCC, AR4, 2007 DEFRA, UK (Department for Environment, Food and Rural Affairs)

Thank You Claire N Parker