# Presentation: 243256

## Summary of Recent IPCC Working Groups Contributions to

**IPCC Third Assessment Report**

**Paul F. McArdle, Ph.D. **
**Energy Information Administration**
**Paul.McArdle@eia.doe.gov**
**presented to the**
**National Energy Modeling System/Annual Energy Outlook 2001 Conference**
**Washington, DC**
**March 27, 2001**

## Intergovernmental Panel on Climate Change (IPCC) Working Groups

- Working group I (WG I)
- The science of climate change - January 2001
- Working group II (WG II)
- Climate change:  impacts, adaptation, and vulnerability - February 2001
- Working group III (WG III)
- The mitigation of climate change - march 2001
- IPCC third assessment report - September 2001

## Results of IPCC Working GroupsWG I - Science of Climate ChangeIPCC Findings - 20th Century

- Global mean temperature has increased by 0.6 C during the 20th century
- Snow cover and ice extent have decreased
- 10% reduction in snow cover since late 60’s
- 10 - 15% reduction in northern hemisphere spring/summer ice extent since 50’s
- Global sea level has risen 0.1 - 0.2 meters during 20th century

## Results of IPCC Working GroupsWG I - Science of Climate Change IPCC Findings - Human Influence

**Results of IPCC Working Groups****WG I - Science of Climate Change**** IPCC Findings - Human Influence**

- New and stronger evidence that most warming observed over last 50 years is attributable to human activities
- It is very likely that 20th century warming has contributed significantly to the observed sea level rise through thermal expansion of sea water and loss of land ice

## Results of IPCC Working GroupsWG I - Science of Climate Change IPCC Findings - 21st Century Projections

- Global mean temperature and sea level are projected to rise under all IPCC scenarios
- Mean surface temperature is projected to increase by 1.4 - 5.8 C.
- Mean sea level is projected to rise by 0.09 to 0.88 meters
- Northern hemisphere snow cover and sea-ice extent to decrease further
- Anthropogenic climate change will persist for centuries even after greenhouse gas concentrations have stabilized

## Results of IPCC Working GroupsWG II - Impacts, Adaptation, and Vulnerability  IPCC Findings - Potential Adverse Impacts

- Reduced crop yields
- in tropical and subtropical areas
- in mid-latitudes for temperature increases more than a few degrees C
- Decreased water availability in many water scarce regions, particularly sub-tropics
- Increased exposure to vector-borne (malaria) and water-borne (cholera) diseases, as well as heat stress
- Increased risk of flooding (to tens of millions) due to heavy precipitation and sea-level rise

## Results of IPCC Working GroupsWG II - Impacts, Adaptation, and Vulnerability  IPCC Findings - Potential Beneficial Impacts

- Increased crop yields in some mid-latitudes for temperature increases less than a few degrees C
- Potential increase in global timber supply from appropriately managed forests
- Increased water availability for some water scarce regions (e.g., Southeast Asia)
- Reduced winter mortality in mid- and high-latitudes

## Results of IPCC Working GroupsWG II - Impacts, Adaptation, and Vulnerability  IPCC Findings - Vulnerability of Developing Countries

- Impacts are worse than to developed countries:
- More flood- and drought-prone areas
- More of economy in climate-sensitive sectors
- High shore protection costs
- Poorer nutrition and health infrastructure
- Less capacity to adapt:
- Limited technology availability, financial capacity, institutional capacity and educational resources

## Results of IPCC Working GroupsWG III - Mitigation of Climate Change IPCC Findings - Nature of Mitigation

- Greenhouse gas emissions are highly dependent on developmental pathway
- costs depend on technological development and timing/level of GHG stabilization
- Mitigation policies will be affected by, and have impacts on, broader socio-economic policies
- air quality; health; economic; etc.
- Lower emissions will require different patterns of energy resource development
- increased efficiency; lower-carbon fuels

## Results of IPCC Working GroupsWG III - Mitigation of Climate Change IPCC Findings - Options to Reduce GHGs

- Significant technological progress since IPCC 1995 report
- wind turbines; hybrid vehicles; fuel cell vehicles
- half of projected increase in global emissions from 2000 to 2020 could be reduced with direct benefits; with the other half reduced at cost of up to $100/tCeq
- Forests, agricultural lands and ecosystems could sequester up to 100 GtC by 2050
- Known technological options could achieve 450-550 ppm CO2 stabilization by 2100

## Results of IPCC Working GroupsWG III - Mitigation of Climate ChangeMajor Conclusions - Costs of Mitigation

- Some emission reductions can be achieved at zero or negative net social costs via no regret opportunities:
- reducing market imperfections
- ancillary benefits (e.g., local air pollution)
- revenue recycling to reduce distortionary taxes
- Annex B1 countries Kyoto Protocol compliance costs vary substantially with and without emissions trading:
- costs are higher in absence of emissions trading
- costs can be reduced further with inclusion of carbon sinks, CDM and other GHGs
- 1Annex B countries: Group of countries included in Annex B in the Kyoto Protocol that have agreed to a target for their greenhouse gas emissions, including all the Annex I countries (as amended in 1998) but Turkey and Belarus.