“The bottom line is, it’s still in our hands, but only just. The ball is slipping through our fingers.”
Dan Lunt is a Professor of Climate Science at the University of Bristol’s Cabot Institute for the Environment. He was one of 200 lead authors from across the globe who contributed to the landmark report published this week – the clearest understanding of the climate crisis we’ve ever had.
Described as a “code red for humanity”, the Intergovernmental Panel on Climate Change’s (IPCC) report has found that everyone on the planet is already being affected by “unprecedented” climate change, some changes are “irreversible”, and even with radical reductions in greenhouse gas emissions, it’s likely we will reach 1.5C of average warming above pre-industrial levels, breaching the target of the 2015 Paris climate agreement.
We are just three months before the UK hosts the crucial climate conference Cop26 in Glasgow, seen by some as the last chance for international governments to prevent climate disaster.
Professor Lunt spoke to the Cable to explain the findings of the report, and what it means for Bristol and the rest of the UK.
What does the alarming report say?
The report represents the best understanding of climate change, based on the work of hundreds of scientists and more than 14,000 reviewed scientific papers. The last of its kind was in 2013.
The most important points to take from it, Lunt says, are: “Firstly, we are more confident than ever that climate change is occuring everywhere, all over the globe. It’s unequivocal that everyone on the planet is affected by climate change.
“Also, the changes are unprecedented in thousands of years at least,“ he added. “As a result, we’re able to say with more confidence than ever before that the changes we’re seeing are made by humans, in particular emissions of carbon dioxide and other greenhouse gases.
“Another really big thing is that we’re able to say with more confidence than before that there will be an increase in extreme events, whether that is rainfall, flooding, heatwaves, droughts, in various parts of the world.”
“If the world is going to keep below the target that has been set by governments of 1.5C of warming to try and avoid dangerous climate change, we’re going to need immediate and far reaching reductions in emissions of greenhouse gases. Without reaching net zero emissions by 2050, it’s extremely likely that we will miss this target.
“We are not currently on track to meet those targets,” he added.
The report sets out different scenarios based on how much we can reduce our carbon emissions. Even the most optimistic scenario, based on rapid reductions, predicts we will reach 1.5C between 2040 and 2060, before temperatures start to fall again later in the century. But in other scenarios where we reduce our emissions less, average global temperatures are predicted to rise to more dangerous levels by the middle of the century, up to 2.4C, causing more extreme impacts and making irreversible changes more likely.
Lunt says: “If we don’t reduce our emissions then by the end of the century, we’ll be looking at a planet as it was 3 million years ago.”
“0.5C doesn’t sound like a big difference because we’re used to big temperature changes within a year, but these numbers are global averages,” he adds. “To put that number in context, the last ice age over the whole globe was only 5C colder than it is today, and that’s a world where half of the UK is covered in a km of ice. So the warming we’ve had already is 20% of an ice age.
“The amount of CO2 in the atmosphere today is more than it has been for the last 2 million years, that’s a new finding. That’s a scale of how unprecedented this is. We’ve pushed 2 million years worth of change into a few decades.”
What will be the impact on Bristol?
Lunt says individual weather events can’t be directly attributed to global warming, but these events are likely to become more common. The report also gives a more comprehensive picture about how climate change is affecting every region of the globe.
Temperature rises in the next few decades are guaranteed because there is a delay before any cuts to emissions take effect. “Even with radical action, we’re still talking about an increase in temperature,” he says. “We’re at 1.1C now, even with immediate and wide-ranging cuts, we’re talking about an extra 0.4C of warming.
“In Northern Europe, we expect with high confidence that the frequency and intensity of heat extremes is going to increase. The science says severe storms will increase. Extreme rainfall and flooding events are all set to increase. These are under all scenarios in the near future.
“Global events will affect Bristol,” he adds. “Bristol is intimately linked to the global economy. Global impacts on agriculture will affect Bristolians, all sorts of changes will affect people in Bristol, directly, or indirectly.”
In the second half of next year, part two and three of this report will focus more on the impacts of climate change and how we can mitigate them.
What does this mean for Bristol’s and the UK’s emission targets?
The report represents the most urgent warning to date that climate action is needed. The UK has pledged to reach net zero carbon by 2050, which fits with the best case scenario for cuts to global emissions. Analysis by Carbon Brief shows we are halfway towards our 2050 target.
Bristol has set itself an even more ambitious target of reaching net zero by 2030, which mayor Marvin Rees recently described as “massively challenging” but essential. Data shows that the city reduced its carbon emissions by more than a third between 2005 and 2017, but that much more rapid reductions – 1.6 times – are needed to reach net zero by 2030.
“The Bristol net zero target is a benchmark that it would be great if all cities could follow,” Lunt says. “Bristol is very progressive in that way. The ambitious targets we’ve set as a city make me very proud to be a Bristolian.
“If we want to meet our targets, many more cities around the globe will have to follow Bristol’s example. It shows that Bristol’s ambitions are in line with global targets.”
The main local battleground on climate issues at the moment is the potential expansion of Bristol Airport. Campaigners from Bristol Airport Action Network (BAAN) said yesterday that the stark warnings in IPCC report clearly showed that expansion, which would increase passenger numbers and carbon emissions, could not go ahead. The decision is currently being decided in a 10-week public inquiry in Weston-Super-Mare.
Looking ahead to November’s climate conference Cop26 in Glasgow, Lunt says the timing of the report is fortunate. “It really is a wake-up call for politicians that if they want to meet these targets there will have to be major reductions in emissions.
“If we want to reach that 1.5C target and things haven’t majorly changed in the next ten years, then it may well be too late by the time of the next report.”
Dan Lunt, who specialises in researching past climates, was one of six scientists at the Cabot Institute for the Environment at Bristol University who contributed to the IPCC report.