Scientists Respond to IPCC Backlash

Fifty-five scientists from the Netherlands released the following open letter about the Intergovernmental Panel on Climate Change (IPCC) and errors discovered in its 2007 report on climate change.

In the letter, they explain how the IPCC works, and how the errors drawing so much attention "do not alter the key finding that human beings are very likely changing the climate, with far reaching impacts in the long run."

Open Letter by Netherlands Scientists on IPCC and Errors in Climate Change 2007 Report

Errors in the IPCC climate change report are being seized by some to discredit climate science. In the Netherlands parliament climate scientists have recently been depicted as 'swindlers' and 'climate mafia'. Such allegations are not supported by the facts and are unwarranted. The fact that IPCC is not infallible does not make its key findings untrue or biased. Still, IPCC should become more generous in acknowledging errors rapidly and openly.

With this open letter from the Netherlands scientific community, we aim to adjust the image that has emerged. We ask to keep the public debate more in accordance to the facts. We discuss the key messages from climate science, the IPCC procedures and the quality control mechanisms of the IPCC. Finally we explain what we will do next to contribute to improvement of the IPCC practice and to the restoration of the tarnished trust in climate science.

The Climate Problem

Since 1990, our knowledge on human made climate change and the understanding of its urgency have rapidly increased. Within the natural sciences, the major components of the climate system are well understood. It is a well established fact that the amount of anthropogenic greenhouse gases in the atmosphere has increased rapidly since the industrial revolution. The major influence of greenhouse gases in the atmosphere on the temperature on the ground is a matter of elementary physics. The increasing amounts of anthropogenic greenhouse gasses in the atmosphere change the heat radiation balance of the earth, which very likely leads to higher temperatures on the ground. Measurements consistently show a world wide temperature increase of about half a degree Centigrade over the past century. The measured temperature increase lags several decades behind the changes in atmospheric composition: with present day greenhouse gas concentrations the temperature is expected to further increase by at least 1°C in the coming decades.

The increase in greenhouse gas concentrations is mainly caused by the way in which coal, oil and natural gas are being used and by deforestation. Major uncertainties exist regarding future greenhouse gas emissions and their impacts. Studies by reputable research groups show that projected emissions of greenhouse gases may lead to a further warming of 1,1 to 6,4°C by the year 2100 (relative to the period 1980-1999). Given the fact that the climate system exhibits tipping points, this may lead to partly unpredictable and possibly far reaching and irreversible impacts on society and nature.

The Copenhagen Accord acknowledges that dangerous human interference with the climate should be prevented. For that reason governments agreed that global warming should be limited to 2°C at maximum (compared to the preindustrial climate). Research has shown that this is economically and technically feasible with emission reduction measures and changes in consumption patterns.

The IPCC and the Fourth Assessment Report

In 1988 the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP) established the Intergovernmental Panel on Climate Change (IPCC) with the aim to provide policy makers regularly with a balanced overview of the state of knowledge on climate change. IPCC is an open network organization in which renowned scientist from all over the world collaborate. These scientists are mainly from universities — including most of the Dutch universities — and research institutes such as in our country the Royal Netherlands Meteorological Institute (KNMI), the Energy Research Centre of the Netherlands (ECN) and the Netherlands Environmental Assessment Agency (PBL). At present 194 countries participate in the IPCC, including the Netherlands.