Has the world abandoned the 1.5C global warming threshold?

With 2024 almost certain to be the warmest in human history, why have countries failed to stay under the 1.5C global warming barrier agreed worldwide?

Coal-fired power station with smoking chimneys against dramatic sunset sky. Harmful fuel usage in big city. Carbon dioxide CO2 emissions as primary driver of global climate change.
Coal-fired power stations are used less and less - but are we doing enough? (Getty)

This year is now almost certain to be not only the warmest in human history, but also the first to breach the 1.5C global warming barrier agreed by governments around the world as a limit to avoid.

Data from the European Copernicus Climate Change Service suggests that the temperature this year will be 1.55C above the levels seen between 1850 and 1900, before emissions started to warm the climate.

The 1.5C threshold is seen as a key point beyond which extreme weather, sea level rises and other negative outcomes are more likely: the 2015 Paris Agreement aimed to limit global warming to below 1.5C.

While the Paris Agreement is accepted to refer to a long-term trend rather than individual years, the breach of the 1.5C above pre-industrial levels will be a symbolic moment.

Yahoo News spoke to leading British climate experts on what the breach means – and whether the world has abandoned the dream of limiting warming to 1.5C.

The momentum behind the shift to renewable energy is already there, and cannot be stopped, according to green transition expert Tomer Shalit, founder of climate data service, ClimateView.

“The world is a very different place to what it was eight years ago. The move away from fossil fuels and towards renewables has too much momentum to be stopped. A nuclear plant’s worth of solar panels is being built every day, global investment in clean technology is running at double the size of coal, oil and gas," Shalit said.

The question is no longer ‘will it happen?’ but instead, ‘how fast?’. Companies and countries that decrease speed or stall the transition will become less relevant on the global stage.”

Donald Trump is widely expected to dial back green regulations and boost oil and gas when he becomes President in 2025, having previously pulled the US out of the Paris Agreement.

Rapid climate action will mean that the world can ‘reverse’ even if this year breaches the 1.5C barrier, says Professor Paul Halloran, professor in ocean and climate science at the University of Exeter and scientist on the Convex Seascape Survey – but it may not be enough.

Prof Halloran thinks that it’s too late to avoid breaching the barrier, “We have missed the window to decarbonise quickly enough to avoid temperatures exceeding 1.5 degrees.

But he says that the International Panel on Climate Change has modelled scenarios in which the world exceeds 1.5C – but still brings the temperature back down, although this will be difficult to achieve.

"To achieve this, we must hit net zero around the middle of this century then go significantly below Net Zero by sucking massive amounts of CO2 from the atmosphere. Net zero doesn’t just mean not burning fossil fuels, it requires a whole range of interventions such as restoring the natural carbon sinks that we have disturbed," Prof Halloran added.

Halloran believes that natural ‘carbon sinks’ such as forests plus ‘blue carbon’, where the sea absorbs more carbon dioxide, will be important.

Datchet, UK. 28th November, 2024. A Flood Alert is in place for the River Thames from Datchet, Berkshire (pictured) to Shepperton Green. River levels are rising on the River Thames as a result of heavy rainfall from Storm Bert and Storm Conall. Therefore, flooding of low lying land and roads is expected to continue today, 28/11/2024. The forecast is currently for no further rainfall. River levels are still slowly rising and we expect levels to remain high over the coming days, however, property flooding is not currently expected. Credit: Maureen McLean/Alamy Live News
Recent flooding has been linked to our warmer climate (Alamy)

“The challenge of doing everything required to get to net zero, then developing and scaling the solutions required to take us well below net zero – technologies and approaches that could each year suck about 20% as much CO2 from the atmosphere as we are currently annually putting into the atmosphere – mean that 1.5C, even by the end of the century, is very unlikely to be achieved," he said.

But it’s still possible to limit the worst effects of climate change, he believes.

“1.5 degrees is not some well-defined threshold, it is an ambition that minimises the risk of experiencing some of the worst climate impacts. If we decarbonise with absolute urgency, we can limit how far beyond 1.5 degrees we go, and each fraction of a degree of warming avoided is one less roll of the dice on triggering dangerous climate tipping points," said Halloran.

Everyone, from academics, policymakers or even members of the general public, now knows that 1.5C will be breached, says Simon Bones, visiting research fellow in climate change science at the University of Bristol.

Bones, the founder and CEO of emission reduction company Genous, believes that while most people are aware the goal will be breached, it should not be abandoned.

“Leaving to one side whether unachievable but aspirational goals actually motivate changes in behaviour, all the climate science is clear that a warmer world creates dangers and problems, and that gets greater the greater the warming – with both extreme weather and less noticeable but equally strong shifts already generating clear challenges for people, businesses and the broader environment," he said.

“None of this will get better, and all evidence is it will get worse, and 1.5C is both a symbolic threshold and a practical one in terms of likely impacts, which have long been documented. This should be a wake-up call to those with the means to change their behaviours and reduce their emissions to do so.”

Global temperatures have been so high through the first 10 months of 2024 that only an implausibly sharp drop in the final two months would prevent a new record from being set.

In fact, it is likely that 2024 will end up at least 1.5C hotter than pre-industrial times, according to data.

"Pre-industrial" refers to the benchmark period of 1850-1900, which roughly equates to the time before humans started significantly heating up the planet, for example by burning large amounts of fossil fuels.

“The goal to avoid exceeding 1.5C is deader than a doornail. It’s almost impossible to avoid at this point because we’ve just waited too long to act,” said Zeke Hausfather, climate research lead at Stripe and a research scientist at Berkeley Earth.

“We are speeding past the 1.5C line an accelerating way and that will continue until global emissions stop climbing.”

Phil Thompson, CEO of Balance Power, one of the UK’s leading renewable energy developers, has been working in the renewable energy sector since 2007 covering biomass, waste to energy, gas peaking, solar and BESS projects.

Global warming, the greenhouse effect and how it happens. (PA)
Global warming, the greenhouse effect and how it happens. (PA)

“It is probably unfair to say the world is abandoning the 1.5C limit. A more accurate representation is that there is now growing acceptance that not enough has been done to date to reach the target, the pace of change is too slow, and it will simply not be possible. We are not giving up on 1.5C, but we are shifting focus towards limiting how much we breach this target and keeping it as low as possible.

"The UK, alongside many other nations, has made significant progress towards climate goals, particularly with its increasing share of renewable energy and growing clean energy investments. However, we need to see coordinated action across the globe – especially from the world’s largest emitters – to make the significant cuts to emissions needed to enable the extent of the breach to be minimised.”

Change in average temperature by decade worldwide from 1910 to 2019, by region.
Change in average temperature by decade worldwide from 1910 to 2019, by region.

Emissions generally grow with income, and with businesses like Genous able to slash the footprint of up to 30% of a richer household’s controllable carbon footprint without impacting quality of life (and while usually generating strong financial returns), there is now more imperative than ever to take personal responsibility for action, and not to wait for politicians or engineers or financiers to save us – not least, because they won’t.