"We're surrounded by fire ... please send help"

My heart sank today on reading of the death toll in Australia's bushfires. Hundreds of houses burnt to the ground and no end in sight.

I was never close to a bushfire in my time in Sydney but during one year fires raged in both the national parks to the north and south. In the north they spread into the ravines which divide the suburbs, coming within maybe ten kilometres of the city centre.

They were so big that in central Sydney the entire sky at night was red, everywhere you looked except east. And in the air was smoke, embers and bits of burnt vegetation.

Sydney is a huge city, maybe seven times the size of London. And across the whole area people could see and feel these bushfires. This gives you some idea of the scale.

It's the same in Melbourne now, many kilometers from the fires.

To give you some idea of just how terrifying it is to be in the middle of this listen to this call to a Melbourne radio station made by a woman trapped in a house with eight others surrounded by flames. Fortunately this has a happy ending as her young brother manages to drive a tractor through to save them.

There's also a lot of social media reports: Google organised map; Twitter; Flickr; Facebook group.

"One thing about Mother Nature. When she gives you a kick in the guts, she gives you a kick in the guts."

CFA bloke speaking to a community in Victoria

Bushfires in Australia are completely natural. Many plants require them to reproduce and it's amazing to see ravaged eucalyptus forest relatively quickly coming back to life.

But there is real reason to suspect that the combination of a severe lack of rain, incredible temperatures plus very strong winds which have worsened these fires are not entirely natural. Studies have shown an increased risk across south-east Australia due to climate change.

Australia Greens Senator, Bob Brown said:

Global warming is predicted to make this sort of event happen 25 per cent, 50 per cent more.

It's a sobering reminder of the need for this nation and the whole world to act and put at a priority our need to tackle climate change.