Global Trends by Martin Khor

Monday 5 February 2007

Beware, global warming is here to stay

The latest scientific report on climate change, launched last Friday, says there is no doubt it is already taking place and things will get far worse.


The media is filled with news on the report on global warming issued by the world’s top climate scientists last Friday.

It may seem strange that its biggest message is that global warming is really taking place, and that human activity is almost certainly the cause. After all, haven’t we known that for years?

Well, these scientists had to come up with such a consensus document as some influential parties have, till now, been denying it.

Most important had been the Bush administration of the United States.  It had withdrawn from the Kyoto Protocol, which committed developed countries to bring down their Greenhouse Gas emissions.

From time to time, statements have come out of the White House that even appeared to doubt the reality or cause of climate change.

Then there are some oil companies that deny that the burning of  fossil fuels by humans have led to climate change. They fear that admitting this would lead to disciplines to reduce oil use.

And there are also a few scientists left who have doubted whether global warming is taking place or how serious that is.

These doubters have thrown some cold water on the policy-makers’ will to act.

The value of the report of the inter-governmental panel on climate change (IPCC) is that it dismisses once and for all the doubts that global warming is caused by humans.

It says that there is “unequivocal” evidence that the world is warming, and that there is a 90% probability that it is caused by human activity.

The IPCC will issue another three reports this year, which will have more detailed information and be more controversial, as they are expected to suggest what actions are needed.

Last week’s report gave frightening enough information. Climate change and its many damaging effects are already taking place.

The recent Johore flood is evidence of this.  Several Malaysian scientists have already explained how climate change contributed to the floods.

The IPCC report describes how changes are already taking place in the atmosphere, the oceans and glaciers and ice caps.  Signs of extreme temperatures include heat waves, new wind patterns, worsening drought in some regions, heavier rain in others, melting glaciers and Arctic ice and rising global average sea levels.

Some basic figures will help us understand the report better. The level of carbon dioxide (the main Greenhouse gas that causes global warming) in the atmosphere was 280 parts per million (ppm) in the pre-industrial era.  It rose to 379 ppm in 2005.

The higher the carbon dioxide in the atmosphere, the warmer will the world be. There would be catastrophic effects if the average global temperature were to rise by 2 degrees or more above the pre-industrial level.

The IPCC report concludes that:

*          If atmospheric concentrations of greenhouse gases (GHG) double compared to pre-industrial levels, this would “likely” cause an average warming of around 3°C.

*          A GHG level of 650 ppm would “likely” warm the global climate by around 3.6°C, while 750 ppm would lead to a 4.3°C warming, 1,000 ppm to 5.5°C and 1,200 ppm to 6.3°C.  Future GHG levels will depend on economic growth, new technologies, policies and other factors.

*          The world’s average surface temperature has increased by around 0.74°C over the past 100 years (1906 - 2005). Eleven of the last 12 years have been among the 12 warmest years since modern records began around 1850. A warming of about 0.2°C is projected for each of the next two decades.

*          The sea-level is estimated to rise due to ocean expansion and glacier melt by the end of the century (compared to 1989 –1999 levels) by 28 - 58 cm.  However, it could rise by up to one metre by 2100 if ice sheets continue to melt as temperature rises.

*          The last time the polar regions were significantly warmer than at present for an extended period (about 125,000 years ago), reductions in polar ice volume caused the sea level to rise by 4 to 6 m.

*          Sea ice is projected to shrink in the Arctic and Antarctic regions. Large areas of the Arctic Ocean could lose year-round ice cover by the end of the 21st century. The extent of Arctic sea ice has already shrunk by about 2.7% per decade since 1978, with the summer minimum declining by about 7.4% per decade.

*          Snow cover has decreased in most regions. The maximum extent of frozen ground in the winter/spring season decreased by about 7% in the Northern Hemisphere over the latter half of the 20th century.

*          It is “very likely” that precipitation will increase at high latitudes and “likely” it will decrease over most subtropical land regions. It is “very likely” that the upward trend in hot extremes and heat waves will continue. The duration and intensity of drought has increased over wider areas since the 1970s.

The report launched last week was a summary for policy makers of “Climate Change 2007: The Physical Science Basis.”  It was produced by some 600 authors from 40 countries.

The IPCC’s second report on climate impacts and adaptation will be launched in on 6 April, the third report on mitigation will be launched in May and the Synthesis Report will be adopted on 16 November.