Australian Broadcasting Corporation: LEIGH SALES, PRESENTER: It's the most comprehensive appraisal of climate change ever undertaken and the news isn't good.
The United Nations' climate change body's new report says the scientific evidence is unambiguous about the warming of the planet and the need for action.
Greenhouse gases are at their highest levels for 800,000 years.
The Earth is on a trajectory for warming of at least four degrees Celsius by 2100. That'll mean more and longer heatwaves and storms and more species extinctions....