1827 - The French scientist Jean Baptiste Fourier recognised a warming effect, the greenhouse effect.

1896 - A Swedish chemist, Svante Arrhenius, calculated rising carbon dioxide levels in the atmosphere, doing predictions of rising global average temperatures.

1957 - Charles Keeling began measurements of atmospheric carbon dioxide, soon identifying that carbon dioxide levels were increasing year by year.

1979 - In the British journal Nature: "The release of carbon dioxide to the atmosphere by the burning of fossil fuels is, conceivably, the most important environmental issue in the world today".

1988 - The Intergovernmental Panel on Climate Change (IPCC) was formed. The panel, which consists of hundreds of scientists from all over the world, assesses scientific literature and provides decision-makers with an objective source of information about climate change.

2007 - "Atmospheric concentrations of CO2 and CH4 in 2005 exceed by far the natural range over the last 650,000 years." "Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average sea level" (IPCC assessment report 4).

Warming of the climate is unequivocal and the health impacts of climate change are now evident and largely unavoidable. These impacts range from the direct effects of extreme weather events such as storms and floods, to water shortages, food shortages, loss of homes and changes in the patterns of infectious diseases. Predictions of global warming have been done decades ago. It is no longer an issue of waiting and seeing but an urgent call for action by all.