The World Bank has warned the planet is on track to warm by four degrees Celsius this century – causing increasingly extreme heat waves, lower crop yields and rising sea levels – unless significant action is taken to cut greenhouse gas emissions.
Scientists say global warming must be kept within two degrees of pre-industrial temperatures to give the world the best chance of avoiding the worst impacts of climate change.
It says that if current promises by nations to curb emissions are met then it is most likely there will be more than three degrees warming. However, under that scenario it warns there is also a 20 per cent likelihood that four degrees of warming will occur by 2100.
If current promises are not met, then the world is “plausibly” on a path to warm by four degrees this century, possibly as early as 2060, the bank says.
The report, titled Turn Down the Heat (executive summary), says if the world experiences four degrees of warming it would:
* See a 150 per cent increase in ocean acidity, leading to the extinction of some sensitive coral reef ecosystems.
* Result in sea-level rise of 0.5 to 1 metres by 2100, with more in following centuries, affecting low-lying islands and coastal communities.
* Lead to more extreme heatwaves, reduced run-off into major rivers and a significant decline in biodiversity, all risking the support systems of humans.
The report says the full impact on human development of a four-degree-hotter world is unknown, making it is unclear whether humanity would be able to adapt.
This new report from the World Bank reminds us that climate change is happening – now. The evidence is clear. No country is immune. If we mobilise today, we can make a difference tomorrow. Learn more here, here, here or here.