If the predictions in yesterday's report by leading climate scientists proved correct, millions living in northern climes would gain from milder winters and a longer growing season but, further south, people would suffer the consequences of intense heatwaves that would kill many unused to extreme temperatures.
Insect pests would proliferate and there would be an increase in malaria; sun-seekers would find the Mediterranean too hot for holidays in July and August.
As the inter-governmental panel on climate change set out yesterday, the Earth is warming faster than at any time in the last 10,000 years and man is causing the increase by burning fossil fuels, cutting down forests and making changes in agriculture.
The changes predicted would cause coastal areas to be inundated and lead to major population changes. They would end the ski industry in Europe, cause the disappearance of many of the world's glaciers on which communities rely for regular summer water supplies, and have serious effects on agriculture.
The growing season for many of the staple crops in Africa would be cut too short for a reliable harvest because of excess heat and lack of moisture, and in Europe the Mediterranean fringe would be too dry for cereal crops.
Many of the world's forests would die because of changes in water supply and the increasing heat.
Night-time average temperatures would increasingly leave much larger areas frost-free, leading to increases in insect life.
Heatwaves would increase over all northern land areas and droughts, already observed to be increasing in Africa and Asia, would become more severe.
According to the report, nearly all land areas, including northern Europe, Asia and the United States, will warm far faster than average, possibly by as much as 8c.
Climate models worked out by giant super-computers have become far more reliable since the last report in 1995.
This, combined with the climate changes observed over two decades, has convinced scientists that something very serious is happening and that it cannot be a natural process.
There is far greater unanimity among the world's scientists over the issue than among politicians.
The floods in parts of northern Europe are entirely consistent with climate-change predictions.