Greenhouse Emissions Must Peak by 2015: IPCC
Urban Ecology News. 2007.11.18
World greenhouse gas emissions must peak by 2015 to limit global temperature rises to 2.0 to 2.4 Celsius over pre-industrial times, says IPCC report.
According to the IPCC "Synthesis Report - Summary for Policy Makers":
Warming of the climate system is evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average sea level.
Temperatures are likely to rise by between 1.1 and 6.4 degrees Celsius and sea levels by between 18 centimetres and 59 centimetres this century.
Most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in greenhouse gas concentrations from human activities.
Global total annual greenhouse gas emissions from human activities have risen by 70 per cent since 1970. Concentrations of carbon dioxide, the main greenhouse gas, far exceed the natural range over the last 650,000 years.
Africa, the Arctic, small islands and Asian mega-deltas are likely to be especially affected by climate change.
Sea level rise would continue for centuries because of the momentum of warming even if greenhouse gas levels are stabilised.
Warming could lead to some impacts that are abrupt or irreversible. About 20-30 per cent of species will be at increasing risk of extinction if future temperature rises exceed 1.5 to 2.5 Celsius.
Warming will put at risk unique and threatened systems, such as polar or high mountain ecosystems, coral reefs and small islands.
Warming will increase the likelihood of extreme weather events, such as floods, droughts and heatwaves.
The poor and the elderly are likely to be hit hardest, and countries near the equator, mostly the poor in Africa and Asia, generally face greater risks such as of desertification or floods.
There is evidence since 2001 that any benefits of warming would be at lower temperatures than previously forecast and that damages from larger temperature rises would be bigger.
Risks of "large-scale singularities", such as rising sea levels over centuries; contributions to sea level rise from Antarctica and Greenland could be larger than projected by ice sheet models.
Governments have a wide range of tools with which to repond to climate change - higher taxes on emissions, regulations, tradeable permits and research. An effective carbon price could help cuts.
Emissions of greenhouse gases would have to peak by 2015 to limit global temperature rises to 2.0 to 2.4 Celsius over pre-industrial times.
The costs of fighting warming will range from less than 0.12 per cent of global gross domestic product (GDP) per year for the most stringent scenarios until 2030 to less than 0.06 per cent for a less tough goal. In the most costly case, that means a loss of GDP by 2030 of less than 3 per cent.
Political response in Australia
The report has prompted comments from political leaders in Australia.
Labor leader Kevin Rudd says the scientists are sounding a warning bell. "This is a call to arms for the nation, a call to arms for the world to act now on climate change before it's too late."
Liberal leader, John Howard says, climate change is a serious challenge, but the world will not end tomorrow because of it. "Like all these things we have to get a commonsense, balanced approach."
Greens Leader Bob Brown says the world's scientists have again made it clear that to avoid dangerous climate change, global emissions must peak by 2015. "What we do, or do not do, about climate change in the next two terms of government will determine the course of human history."
The Greens have launched a Climate Change Action Plan, which details the role Australia could play in the global effort to keep global warming under the dangerous threshold of 2°C.
Links
Source: Climate policies under scrutiny ahead of Bali summit. ABC. 2007.11.18
Source: Highlights of UN Climate Panel Summary Report. Reuters. 2007.11.17
Source: World Won't End Tomorrow Due to Climate Change: Howard. Sydney Morning Herald. 2007.11.18
Refer: Synthesis - Summary for Policy Makers. Fourth Assessment Report. Intergovernmental Panel on Climate Change. 2007.11.17
Refer: Six Step Climate Change Action Plan (PDF). Australian Greens. 2007.11