Scientists issue first batch of key climate report

I think everybody - no matter what walk of life or profession - should try to read the summaries for policy makers of the reports issues by the world’s scientific authority on climate change - the Intergovernmental Panel on Climate Change (IPCC). IPCC reports are based on peer reviewed and published scientific and technical literature. No matter what people do, where they live, what political beliefs they have - one day they will be affected by climate change in their professional and personal life. However, for anybody who is really too busy to do so, I am providing a "summary of the summary". This is the modified and shortened version of an article I've published on a business publication.

A milestone in climate science?
A new report issued earlier this month by the IPCC said the scientific community is at least 90% certain humans are responsible for the problem. The Panel also made fresh predictions and clarified many uncertainties. The key issue now is whether a crucial temperature threshold risks being breached – and what to do about it.

This report follows the Third Assessment Report (TAR), issued in 2001. The IPCC Working Group 1 report- Climate Change 2007: The Physical Science Basis - is part of the Fourth Assessment Report. It assesses the latest scientific knowledge of the natural and human drivers of climate change, observed changes in climate, the ability of science to attribute changes to different causes, and projections for future climate change.

Based on recent observations and measurements, scientists now say humans are responsible for climate change with at least 90% certainty – higher than in the TAR, which placed it at 66%. Scientists have also improved their ability to predict future climate change. They adjusted predictions for temperature rises over this century and said the rate of warming has recently increased. The 11 warmest years on record have all occurred in the past 12 years. The second half of the 20th century was the warmest period in the northern hemisphere for at least 1,300 years.

Confidence in regional climate change projections has also improved, thanks to new models and computer technology. Scientists have now clarified a number of issues which had been left partly unresolved in the TAR. For example, both volcanic eruptions and man-made aerosols have had a relative cooling effect, offsetting some of the warming that would have otherwise been observed.

There are now fewer uncertainties on so-called feedbacks – effects of climate change which can accelerate or decelerate the rate of climate change. Scientists clarified that increased temperatures will cause a decay of organic matter rather than speeding plant growth. Some had hoped increased plant growth would slow down climate change. Some economists had argued this might be a positive impact of climate change, which could potentially increase agricultural yields in parts of the world. However, scientists now say plants and soils will absorb less CO2 as the world warms. It is now thought that this may accelerate the rate of warming because a larger fraction of the CO2 emitted will remain in the atmosphere, and the magnitude of climate change caused by a given level of emissions will be larger than previously thought.

In reaction to the report, the European Commission said that without more action to limit greenhouse gas emissions, the global average temperature is likely to rise by a further 1.8-4.0°C this century, after increasing by over 0.7°C in the past 100 years. “Even the low end of this range would take the temperature rise since pre-industrial times to above 2°C, the level at which there could be irreversible and possibly catastrophic consequences,” the Commission said in a statement.

European Union (EU) climate change policy is based on a target agreed by member countries to keep global temperature increases below a 2°C rise compared to pre-industrial temperatures. Many scientists consider this limit to be crucial for avoiding the most catastrophic and irreversible climate change impacts.

The executive director of the United Nations Environment Programme (UNEP) Achim Steiner told a press conferencel. “It is critical that we look at the report not only as a milestone but truly as a moment where the focus shifts from whether climate change is linked to human activities – to what on earth are we going to do about it,” he said.
“Anyone who would continue to risk inaction on the basis of the evidence presented here will one day in the history books be considered irresponsible.”

The IPCC was set up in 1988 by UNEP and the World Meteorological Organization (WMO). It published previous comprehensive reports in 1990, 1995 and 2001. The working group 1 report was produced by around 600 authors from 40 countries. Over 620 expert and government reviewers also participated. Representatives from 113 governments reviewed and revised the summary line-by-line during the course of a week-long meeting in Paris, before adopting it and accepting the underlying report. The IPCC will issue the two other reports later this year.