We need to act on climate change now – by Professor David Karoly

Global warming has been discussed often over the past two years in newspaper articles and opinion pieces, in the lead-up to the last election and as the Government has tried to introduce its Carbon Pollution Reduction Scheme.

Is there a real scientific debate about climate change or is this just political manoeuvring? If climate change is real, is it due to humans or is it natural? How bad will it get? How will it affect people, including human health? These are some of the many questions that I am asked regularly, and below I try to provide some answers.

In 1988, due to growing concerns about climate change and its possible impacts, the governments of the world set up an independent agency, under the auspices of the World Meteorological Organization and the UN Environment Program, called the Intergovernmental Panel on Climate Change (IPCC).

Its role is to undertake comprehensive, objective assessments of the latest scientific, technical and socio-economic literature produced worldwide relevant to understanding the risk of human-induced climate change, its observed and projected impacts, and options for adaptation and mitigation. These assessments are required to be policy relevant but policy neutral, and contain no recommendations.

The IPCC’s Fourth Assessment Report was written by hundreds of scientists, reviewed by thousands more, and more than 100 governments, then approved unanimously by all the governments and released in 2007 (this assessment is available from www.ipcc.ch ).

Independent assessments by the US National Academy of Sciences and the US Climate Change Science Program reached the same conclusions as the IPCC. The IPCC conclusions on climate change science were:

● “Warming of the climate system is unequivocal”;
● “Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations”;
● “The best estimate of the increase in global average surface temperature in the 2090s relative to the 1990s for a high emission scenario is 4.0°C (likely range is 2.4°C to 6.4°C)”;
● “Anthropogenic warming and sea level rise would continue for centuries due to the time scales associated with climate processes and feedbacks, even if greenhouse gas concentrations were to be stabilized”.

The IPCC assessment of the impacts of climate change on human health concluded that “climate change currently contributes to the global burden of disease and premature deaths”. Climate change is likely to:

● increase malnutrition and consequent disorders, including those relating to child growth and development;
● increase the number of people suffering death, disease andinjury from heatwaves, floods, storms, fires and droughts;
● change the range of some infectious disease vectors;
● bring some benefits to health, including fewer deaths from cold,although it is expected that these will be outweighed by the negative effects of rising temperatures worldwide, especially in developing countries.

More recently, the International Scientific Congress, Climate Change:Global Risks, Challenges & Decisions in Copenhagen in March 2009, attended by more than 2,500 delegates from nearly 80 countries, concluded:“Recent observations show that societies are highly vulnerable to even modest levels of climate change, with poor nations and communities particularly at risk. Temperature rises above 2°C will be very difficult for contemporary societies to cope with, and will increase the level of climate disruption through the rest of the century.”

The scientific conclusions on human-induced climate change and its impacts on health are clear. Our society must act very quickly if it wants to minimise these risks to our health, and primary health care will play an important role.
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Professor David Karoly is an ARC Federation Fellow in the School of Earth Sciences at the University of Melbourne. Funding support from the Australian Research Council is gratefully acknowledged.

This article appeared in the Medical Observer under the Doctors for the Environment Australia column