Key Points:

Fires of unprecedented ferocity are sweeping around the world, fuelled by global warming and misguided environmentalism.

Dubbed "megafires", they rage over thousands of miles at 1,000C and create their own weather, even triggering tornadoes.

Rapidly increasing in number, they are often unquenchable by any human efforts, burning unchecked until they reach coasts or are put out by heavy rainfall.

The devastating fires that have ravaged Greece killed at least 63 people and charred 482,000 acres of land.

This summer, as record heatwaves hit much of southern Europe, more than 1.9 million acres have gone up in smoke .

Matters are even worse in the United States, where 20 years ago, fires burning over 5,000 acres were relatively rare.

In the past 10 years, however, there have more than 200 conflagrations 10 times the size.

Last year, 9.6 million acres of the country were devastated, beating an all-time record set 2005.

This is the sixth time in the past decade that a record year has immediately been surpassed in the following 12 months.

A year ago the Australian state of Victoria suffered 200 fires in a single day.

There have also been megafires in France, Spain, Portugal, Canada, Russia, Mongolia, Indonesia, South Africa and Brazil.

Experts agree that they are caused partly by droughts and higher temperatures brought by global warming, but they also point to conservation practices which have discouraged controlled burning of forests and caused a huge build-up of up to 30 of 40 tons of tinder dry kindling on each acre of ground.

Once lit n by lightning, arson or human error n they produce 20ft flames and generate temperatures of up to 1,200C.

At this intensity they generate their own winds.

One such fire caused tornados near Canberra in 2003.

Professor Stephen J Pyne, an expert at Arizona State University called the fires "climatic tsunamis", and Kevin O'Loughlin, the head of Melbourne's Bushfire Co-operative Research Centre added: "They cannot be controlled by any suppression resources that we have available anywhere in the world."