Climate concern stronger than ever, says IPCC

Posted: 19 November 2007

The planet is likely to experience "irreversible" impacts if the increase in global temperature is not brought under control. For example, if temperature rises above about 3.5 degrees C, between 40 per cent and 70 per cent of the species assessed might be at increased risk of extinction, says the fourth and final report from the International Panel on Climate Change before the Climate Convention meeting in Bali in December.

The IPCC's Summary for Policy Makers underlines the urgency to act to reduce greenhouse gas emissions alongside the economic costs of a transition to a low carbon society.

Map of surface warming
Map of surface warming
Projected surface temperature changes for the late 21st century (2090-2099) under the IPCC A1B ('balanced energy') scenario. All temperatures are relative to the period 1980-1999. This shows warming greatest over land and at most high northern latitudes and least over Southern Ocean and parts of the North Atlantic Ocean, continuing recent observed trends in contraction of snow cover area, increases in thaw depth over most permafrost regions, and decrease in sea ice extent. Credit: IPCC
It argues strongly in favour of stepping up action to adapt to the changing climate.

“Neither adaptation nor mitigation alone can avoid all climate change impacts. However, they can complement each other and together can significantly reduce the risks of climate change,” says the report.

It highlights five “reasons for concern” which are now stronger than before. This is because scientists now conclude that they may happen at lower increases in temperature or because the risks may be larger than had previously been supposed.

Biodiversity hotspots

These include the impacts on species and biodiversity hotspots as temperatures rise including polar and high mountain communities and ecosystems.

The report says that 20 per cent to 30 per cent of the plant and animal species assessed are likely to be at increased risk of extinction if global average temperatures exceed 1.5 degree C to 2.5 degree C over late 20th century levels.

It also points to the likelihood of “irreversible” impacts. For example if temperature increases exceed about 3.5 degrees C, between 40 per cent and 70 per cent of the species assessed might be at increased risk of extinction.

Increases in sea surface temperatures of 1-3 degrees C are projected to result in more “frequent coral bleaching events and widespread mortality”·

Oceans and seas may become more acidic as they absorb rising levels of carbon dioxide and the impacts on “marine shell-forming organisms” like coral reefs.

Droughts and floods

Other reasons for concern focus on the risks of extreme weather events with higher confidence in the projected increases in droughts, heatwaves and floods as well as their adverse impacts.

There is concern too that the poor and the elderly in low-latitude and less-developed areas including those in dry areas and living on mega-deltas are likely to suffer most.

There is high confidence that by mid-century “many semi-arid areas, for example the Mediterranean basin, western United States, southern Africa and northeast Brazil, will suffer a decrease in water resources due to climate change”.

The IPCC warns that any benefits linked with climate change will be gone after more modest temperature rises. It says new observations linked with the Greenland and possibly Antarctic ice sheets may mean that the rate of ice loss will increase above previous forecasts.

Achim Steiner, UNEP Executive Director, said: "This is perhaps the most essential reading for every person on the planet who cares about the future...While the science will continue to evolve and be refined, we now have the compelling blueprint for action and in many ways the price tag for failure — from increasing acididification of the oceans to the likely extinctions of economically important biodiversity”.

"Today’s final synthesis report translates the complex science into a lingua-franca so that governments meeting in Bali can not only understand the challenge but be empowered to act collectively on a decisive post 2012 emission reductions regime,” he added.

Poverty and conflict

The summary makes a strong link between climate change and the wider challenges facing particular developing countries a result of issues like poverty, unequal access to resources, conflict and disease.

On an optimistic note, it points out that combating climate change does not have to damage or derail economies.

“There is high agreement and much evidence of substantial economic potential for the mitigation of global greenhouse gas emissions over the coming decades” if governments adopt the right policies and incentives, it says.

Bringing down global carbon dioxide emissions to 2005 levels by 2030 will require a big shift of investment patterns –“although the net additional investment required ranges from negligible to five to 10 per cent,” concludes the report. It says biggest prospect for emissions cuts comes from buildings, followed by industry and energy supply, agriculture and forestry.

Sea rise inevitable

Martin Khor, Director of the By Martin KhorThird World Features, adds this personal comment:

The 23-page synthesis report from IPCC makes sober reading and makes one wonder how life on Earth is going to survive when such seemingly insurmountable challenges abound. For example, the panel’s chair Rajendra Pachauri said that even if emissions were curbed and Greenhouse gases in the atmosphere remained the same as now, sea levels would rise by between 0.4m and 1.4m because sea water would continue warming up, which makes it expand. “This is a very important finding, likely to bring major changes to coastlines, and inundating low-lying areas, with a great effect in river deltas and low-lying islands,” he said. The report involved 2,500 scientific expert reviewers and 1,250 authors as well as policy makers from over 130 countries. That’s why it enjoys such high prestige. The report’s main message is that warming of the climate system is “unequivocal”, and this is accompanied by increasing global air and ocean temperatures, rising global average sea level and reductions of snow and ice. One of the alarming effects is the increasing rate in global sea level rise, from 1.8mm a year to 3.1mm a year from 1961 to 1993. Sea level rise has been due to thermal expansion and the melting of glaciers, ice caps and the polar ice sheets. The projected sea level rise at the end of the 21st Century will be 18-59cm. Pachauri warned that warming would cause some impacts that are “abrupt or irreversible.” For example, partial loss of ice sheets on ice polar land could imply metres of sea level rise; major changes in coastlines and inundation of low-lying areas, and great effects in river deltas and low-lying islands.

Regional impactsThe report looks at the impacts by regions. Shockingly, in Africa by 2020, between 75 million and 250 million people are projected to be exposed to increased water stress. And in some countries, yields from rain-fed agriculture would be reduced by 50%. In Asia, the key problems are:

  • By the 2050s, freshwater availability in Central, South, East and South-East Asia, particularly in large river basins, is projected to decrease;
  • Coastal areas, especially heavily populated mega-delta regions in South, East and South-East Asia, will be at greatest risk due to increased flooding from the sea and rivers;
  • Endemic morbidity and mortality due to diarrhoeal disease primarily associated with floods and droughts are expected to rise in East, South and South-East Asia due to projected changes in the hydrological cycle.
The report shows that global warming is already taking place. Eleven of the last 12 years (1995-2006) rank among the 12 warmest years in the instrumental record of global surface temperature (since 1850). In the past 100 years there has been a rise of 0.74°C in temperature. Arctic sea ice extent has shrunk by 2.7 per cent per decade, with larger decreases in summer of 7.4 per decade. Mountain glaciers and snow cover on average have declined in both hemispheres. The report also projects an increase of global emissions by 25-90 per cent between 2000 and 2030, if nothing is done. For the next two decades a warming of about 0.2°C per decade is projected. Even if the concentrations of all greenhouse gases and aerosols had been kept constant at year 2000 levels, a further warming of about 0.1°C per decade would be expected. Afterwards, temperature projections increasingly depend on specific emission scenarios.

What the scientists in IPCC have laid out in scientific terms is going to be considered by policy makers at Bali when they discuss the methods and means to combat climate change.

A longer version of the Third World Nerwork Features article first appeared on The Malaysian Star newspaper. (See www.twnside.org.sg)

Note: The 23-page IPPCC report is a synthesis of three other reports (on the science, the impact of and policies to mitigate climate change) that the IPCC had issued earlier this year.

Three working group reports, as well as the Summary, can be downloaded at www.ipcc.ch.