Suelo dead vlei Impressions that the battle against global warming is being won are misleading. In many ways, the struggle has only just begun - both on scientific and political fronts - while for many developing countries, dealing with its potentially disastrous impact is becoming increasingly urgent. Most scientists now agree that human-induced global climate change poses a serious threat to both society and the Earth's ecosystems. But what is climate change? How will it affect developing countries? And what can be done to reduce the threats it poses? Gases including carbon dioxide, nitrous oxide, methane and water vapour trap heat from the sun within the atmosphere. Acting like the panes of glass in a greenhouse, they ensure that temperatures close to the Earth's surface are much warmer than they would otherwise be. In this way, the greenhouse effect makes life as we know it possible. Dead vlei con sombra But this system has recently come under heavy pressure. Since the Industrial Revolution, humankind has been extracting and burning fossil fuels at increasing rates, releasing significant amounts of greenhouse gases into the atmosphere. As concentrations of greenhouse gases have increased, so has the strength of the greenhouse effect. Scientists around the world are using computer models to try to predict how global climate is likely to be affected by this enhanced greenhouse effect in the years ahead. An important part of their work is producing scenarios of what the future climate may look like, based on a combination of past and current observations, and predicted levels of future emissions. Since the early 1980s, this research has led to the conclusion that current trends in climate change are likely to cause an increasing number of threats to the natural world and to human societies. Since 1988, governments have delegated the task of reaching a scientific consensus on climate change to the Intergovernmental Panel on Climate Change (IPCC). Iceberg Its third and most recent assessment, published in 2001, suggests that "there is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities". The report also states that average global temperatures are projected to increase by 1.4 to 5.8 degrees Celsius over the next 100 years because of the enhanced greenhouse effect. Due to this warming, glaciers and the polar ice caps are expected to melt, causing sea levels to rise by between nine and 88 centimetres in the coming century. The IPCC also expects significant changes to patterns of rainfall — including monsoons — and more extreme weather events. These potential effects highlight the need for a coordinated and scientifically based international response.