Could we face a mass extinction of human beings in our lifetime? As global temperatures rise and this summer's bushfires devastate the Australian landscape, it's a worst-case scenario that is beginning to be seriously discussed.
Scientists despairing over the deadly bushfire season sign an open letter to Australia's leaders calling on them to abandon partisan politics and take action on climate change.
Conservative estimates put the final cost of the current Australian bushfires well into billions of dollars, while some analysts say they could set back the economy $20 billion in lost output.
