'Tipping points' could exacerbate climate crisis, scientists fear

IPCC report 'underestimates potential of these key dangers to send Earth into spiral of runaway climate change'

• World leaders 'have moral obligation to act' after UN climate report

Key dangers largely left out of the IPCC special report on 1.5C of warming are raising alarm among some scientists who fear we may have underestimated the impacts of humans on the Earth's climate.

The IPCC report sets out the world's current knowledge of the impacts of 1.5C of warming and clearly shows the dangers of breaching such a limit. However, many scientists are increasingly worried about factors about which we know much less.