Climate change: top climate scientist 'very pessimistic' world can still limit temperature rise to 2C

A leading climate scientist is “very pessimistic” about the world meeting its Paris Agreement targets - but says it is vital for governments to keep slashing emissions to limit the disastrous consequences.

Professor Robert Watson of the Tyndall Centre for Climate Change - and former chairman of the Intergovernmental Panel on Climate Change - told BBC's Today Programme on Thursday (20 July) that failure to do so will result in more heatwaves, floods, sea level rise, crop failure and health problems.

Much of Southern Europe and Northern Africa are already in the grips of back-to-back heatwaves, which have caused wildfires and broken temperature records.

Almost every country on Earth signed up to the Paris Agreement in 2015 to limit global temperature rise to 1.5C - or 2C at the very least. But eight years later, Professor Watson warned emissions were continuing to rise, and current global policies had us on track for around 2.5C of warming by the end of the century.

The UK was one of many countries which also pledged to go "net zero" - meaning the amount of greenhouse gases being emitted into the atmosphere were balanced out by those absorbed - in the UK's case, by 2050.

But Mr Watson said current emissions need to be slashed in half before 2030 to have any chance of reaching the Paris goals. If that target was missed, however, he said it was vital people and governments did not give up.

“I think most people fear that if we give up on the 1.5C, which I do not believe we will achieve - in fact I’m very pessimistic about achieving even 2C - but if we allow the target to become looser and looser, higher and higher, governments will do even less in the future," he said.

“We need to try and hold governments to start to act sensibly now and reduce emissions. But even governments with a really good target, like the United Kingdom, don’t have the policies in place, don’t have the financing in place to reach those goals.”

Scientists have previously warned that allowing the global average temperature to reach 1.5C could trigger irreversible tipping points that would heat the Earth to unpredictable and dangerous levels - where humans have increasingly little control over how much it continues to warm up. The Earth has already warmed by around 1.2C since the pre-industrial era.

In response to a question about the economic impacts on people of cutting emissions rapidly, Prof Watson said: “It’s in their absolute best interest to tackle climate change, net zero by 2050, large reductions this decade.

“If we don’t, we’re going to see more heatwaves, more adverse effects on health, we’re going to see agriculture food production threatened, we’re going to see problems with water quantity and water quality," he continued.

“We’ll see more floods, more sea level rises displacing people on coastal areas, lots of adverse health effects.”