IPCC AR5 – Science on Climate Change and future projections

for South Asia

Broad Outline-

•Highlights of IPCC’s Fifth Assessment Report•Comparison of the Fourth and Fifth Assessment Reports•Challenges posed by climate change for South Asia•Key messages for South Asia.

Highlights of AR 51. Human activity- greater than 95% chance that human

activities are the dominant cause of observed warming since the 1950s.

1. Global changes- estimated warming of 0.85 degrees Celsius since 1880, with the fastest rate of warming in the Arctic.

1. Sea- level rise- Greater that 66% chance that the Arctic Ocean will be ice free during a greater part of the summer before 2050 under a high emission scenario.

Global mean warming since 1951 (°C)

Solar, Volcanic

Aerosols

CO2, CH4, N2O

Anthropogenic

Internal Variability

Observed

Fig. TS.10

Human influence on the climate system is clear.

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3

Human influence on the climate system

Fig. SPM.10

Limiting climate change will require substantial and sustained reductions of greenhouse gas emissions.

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4. Surface warming pause- the recent reduction in surface warming is probably due to a redistribution of heat in the ocean, volcanic eruptions, and the recent minimum in the 11-year solar cycle.

5. Cumulative carbon budget- a GHG emissions budget of 840Gt of carbon has been identified. More than half of that (over 531GtC) has already been emitted.

6. Land based food systems- climate change to affect food security in areas where most of the world’s food production occurs.

Comparison between AR4 and AR5

• Global sea level is expected to rise more by 2100 than previously projected.

• There is less confidence that global average rainfall has increased in the past, but greater confidence that it will increase in the future.

• No change to earlier conclusion regarding trends in flooding.

• No change to earlier conclusions about the likely range of equilibrium climate sensitivity.

Challenges for South Asia• Temperature rise- average annual temperatures could rise by

more than 2°C over land in most of South Asia by the mid-21st century and exceed 3°C under a high emissions scenario.

• Rainfall trends- by mid-21st century southern areas of Asia will experience more rainfall. Rainfall will be more extreme near the centres of tropical cyclones making landfall in south asia.

• Sea level rise- magnitude of sea level rise by the century’s end implies increased risks for South Asia’s coastal settlements particularly if combined with changes in cyclone frequency or intensity.

• Coastal systems- sea level rise will lead to submergence, coastal flooding, and erosion.

• Climate change will cause declines in agricultural productivity in many sub-regions of Asia, for crops such as rice and wheat. This could lead to higher food prices and living costs, malnutrition, and worsened rural poverty.

• Marine systems- higher latitudes will see more biodiversity while marine population will decline in tropical latitudes.

• Flood damage- risk of floods poses a threat to infrastructure, livelihoods, and settlements.

• Heat related mortality is another major challenge.

Annex I: Atlas of Global and Regional Climate Projections

Projected Precipitation change in South Asia

Key messages for South Asia

• South Asia’s climate is already changing and its impacts are already being felt.

• Mitigation for decarbonizing the economy is absolutely essential to reduce the impacts of climate change.

• Some low carbon options may be less costly in the long run but could offer new economic opportunities for South Asia.

• South Asia stands to benefit from integrated climate adaptation, mitigation, and development approaches.

Thank You!