Kate Humble and Simon Reeve experience the frontline of wildfire-fighting in New South Wales, Australia. Every year, across the world, hundreds of thousands of wildfires burn an area the size of India and affect the lives of millions of people. Australia has just experienced its hottest year on record and the most devastating bushfire season in a decade. Temperatures have reached up to 45 degrees and hundreds of fires have burned across a state the size of France. Some blazes have reached the size of Manchester, Birmingham and Edinburgh combined.