Whatever the arguments about causes, there is no doubt that the world has been getting considerably warmer over the last 50 years and much warmer over the last 20 years. Mean average global temperature has risen by 1.4 degree C over the last 100 years and it has now speeded up and almost all the hottest years in the last 100 years have been in the last 20 years. Mean annual temperatures are now increasing by 0.2C per decade. Recent years have seen rising temperatures in many parts of the world and some places are now becoming almost uninhabitable. But the increase in temperatures has not been geographically even and nor have its effects. The polar regions have been warming much faster than other areas, and as snow and ice cover shrinks so does the ability to reflect sunlight. The permafrost areas of northern Russia and Canada are beginning to thaw. Europe and the Middle East have also warmed fast and some parts of the world are now becoming uninhabitable. This has major consequences in terms of agriculture, social breakdown and mass migration. Global warming also generates warmer oceans and rising sea levels. We are seeing the effects of this in the increase in the number of major hurricanes and storms in the Atlantic hitting the East coast of north America and then Western Europe with consequent flooding. But the real risks are in areas like the Bay of Bengal where tropical cyclones generate massive flooding in low lying Bangladesh. Some Pacific island states are also under considerable threat from rising sea levels as are big cities like London, New York and Shanghai. The costs of global warming are unequally distributed and are being felt most strongly in many of the world's poorer areas like the Sahel belt of Africa where more frequent droughts are displacing millions of people. This is generating arguments for international climate justice.