We are heading toward IPCC's 1.5 C threshold of warming, but all is not lost

As we edge ever closer toward that 1.5 C, it may leave one with a sense of defeat, of helplessness, that we have failed and that we might as well give up. But that shouldn’t be the case.

'Our world needs climate action on all fronts — everything, everywhere, all at once,' says UN Sec. Gen.

A Black woman with a basket on her head wades through a flooded field.
Bernadette Handing carries pearl millet on her head as she plods through a submerged sorghum field after heavy rain in Kournari village, on the outskirts of Ndjamena, Chad on Oct. 26, 2022. A recent report by World Weather Attribution concluded that climate change exacerbated heavy rainfall leading to large scale flooding in highly vulnerable communities in West Africa. (Mahamat Ramadan/Reuters)

When the Paris Agreement was adopted by 196 countries in 2015, the goal was to limit global warming to 2 C above pre-industrial levels (1850–1900) by the end of the century. In 2018, that goal was shifted to limiting it to 1.5 C in order to avoid some of the worst global catastrophes.

But that 1.5 C threshold is slipping away.

Monday's IPCC synthesis report (referred to as AR6) notes that although we are more likely than not to reach 1.5 C in the "near term," it could drop back below that by the end of the century. 

"It has become increasingly clear that, on our current path, that we will reach that 1.5-degree limit sometime in the 2030s," UN Secretary-General Antonio Guterres said following Monday's IPCC report. 

Right now, the planet has warmed between 1.1 C and 1.3 C, and we are already seeing the repercussions, from increased deadly wildfires and flooding to droughts. 

As we edge ever closer toward that 1.5 C, it may leave one with a sense of defeat, of helplessness, that we have failed and that we might as well give up. But that shouldn't be the case.

"The conclusions from the last IPCC report were so clear. They said every bit of warming matters. And if we give up, we are doomed," said Katharine Hayhoe, Nature United's Global Chief Scientist. 

In fact, here's the good news: Before the Paris Agreement, the world was on track to reach 3.5 C of warming before the end of the century. However, since then, we are on track to reach 2.5 C. But with announced pledges from countries, it could limit warming to 1.7 C, and if we reach net zero by 2050, it could limit warming to 1.5 C.

The point? Every action policymakers and industry leaders take in reducing greenhouse gas emissions means less CO2 in the atmosphere, which will limit warming. And every degree matters. 

To talk or not talk about 1.5 C

It was a bit surprising to see the acknowledgement in Monday's report that we are more likely than not to surpass 1.5 C, as there has been some debate as to whether scientists should even mention the fact that we are likely to miss the 1.5 C target. 

In 2020, the group Scientist Rebellion was formed by scientists from around the world demanding more action. They have taken to the streets in civil disobedience, by blocking roads, protesting and pasting climate-related articles to places such as ScottishPower, a gas and electric company.

Most recently, they penned an open letter that in part said that governments should "make clear the inevitability of missing the 1.5 C goal as laid out by the IPCC in its latest [AR5] assessment."

Climate scientist Peter Kalmus is one of the signatories. (His views on the matter are his own, and do not represent his employer, NASA).

"I just think it's time for us to be grownups. Basically, we have to look at what's really happening and respond to it. And if we're not willing to look at what's really happening, and we just try to not think about it, then we can't stop it," he said.

"We have to look look very carefully, figure out the causes and say, oh, yeah, okay: it's the fossil fuel industry. I think everyone knows that. But for some reason, there isn't a kind of public collective will to end the fossil fuel industry, which is the reason the politicians aren't doing it: because they're not being pushed to do it by the public."

WATCH | UN report outlines what its calls a 'survival' guide' for humanity: 

Scientists give ‘final warning’ on climate change in UN report

6 months ago
Duration 1:54
Top climate scientists released their final assessment report on climate change, declaring this is the last chance to limit human-caused global warming to 1.5 C above pre-industrial levels before the damage becomes irreversible.

Hayhoe looks at the messaging somewhat similarly, but has a slightly different take.

"My messaging on 1.5 would be: according to the decisions that we are making today, we are going to pass it. So clearly invoking the agency. When you don't show that there's any human agency, that's when people just feel like, 'Oh, well, we're doomed. We're tied to the railroad track, the locomotive is bearing down, and that there's nothing we can do,'" she said.

"But if I say, according to the decisions we're making, we are not going to make this threshold. Now, every little bit matters. And we can make a difference."

And it's important to realize that even if we do hit 1.5 C of warming, it doesn't mean that we will necessarily stay there.

Déjà vu all over again

The science of CO2 emissions and their consequences was well established almost two centuries ago.

"It was really clear that we had a problem by the mid– to late–1970s. Some of the core science was worked out in the 1800s. And then really important stuff was worked out by 1946, or something like that," said Danny Harvey, a professor at the University of Toronto, whose work was cited in the IPCC's first report in 1990.

That report found that under a business-as-usual scenario where emissions of greenhouse gasses go unabated, we could see a rate of global warming of roughly 0.3 C per decade (with an uncertainty range of 0.2 C to 0.5 C per decade).

However, recently the U.S. National Oceanic and Atmospheric Administration (NOAA) found that global temperatures have warmed 0.08 C per decade since 1880. Good news, right? Not so fast.

Since 1980, that rate of increase has been more than twice as fast at 0.18 C per decade.

It's interesting to note that the year the IPCC's first report was issued was also the year that Earth first hit a startling new record-breaking temperature.

WATCH | Climate misinformation is having an impact: 

Think you’re immune to bogus climate claims? Think again

6 months ago
Duration 8:05
Even if you scroll past the videos and social posts making false claims about climate change, you’re not immune. A growing body of evidence shows that misinformation is having an impact, even if you never fall down the rabbit hole.

At the time, 16 senators sent then President George Bush a letter calling for more leadership to address global warming. In a 1991 United Press International story, journalist Rob Stein wrote that, "Negotiations on an international treaty to limit industrial emissions linked to global warming are set to begin in Washington in February." 

Yet, here we are.

The story also included a quote from the letter to President Bush.

"'It would be a grave mistake for us to believe we could postpone action and not face the most serious consequences in the future,' the senators said. 'The scientific data released today provides more evidence and more reason to act.'"

Today, it's déjà vu all over again, with the same call to action, but with far stronger data and language.

"As it shows, the 1.5-degree limit is achievable," Guterres said of Monday's report. "But it will take a quantum leap in climate action … In short, our world needs climate action on all fronts — everything, everywhere, all at once."

More action means more hope

Kalmus is frustrated by the lack of clear action on cutting greenhouse gas emissions.

"I thought by 2023, by this level of climate emergency, that the public would have prioritized taking action by now and would have been voting out politicians that refuse to take action, and voting in politicians who would take action," Kalmus said. "I thought the media would be reporting this crisis, you know, with bigger fonts than they report the Oscars by this point in 2023. This does not seem to be the case yet."

But after Monday's IPCC report, he may have more hope. 

Guterres proposed plans for G20 countries to join a Climate Solidarity Pact where all the big greenhouse gas emitters commit to extreme cuts in emissions in "an effort to keep 1.5 alive." He is proposing a number of things including: 

  • No new coal and the phasing out of coal by 2030 in OECD countries and 2040 in all other countries.
  • Ending all international public and private funding of coal.
  • Ensuring net zero electricity generation by 2035 for all developed economies and 2040 for the rest of the world.
  • Ceasing all licensing or funding of new oil and gas — consistent with the findings of the International Energy Agency.
  • Stopping any expansion of existing oil and gas reserves.
  • Shifting subsidies from fossil fuels to a just energy transition.

If these actions are taken — though it may be hard to fathom considering the U.S. agreed just last week to a new oil drilling project in Alaska despite President Biden saying he is committed to taking climate action — there is the possibility that we may drastically reduce CO2 emissions. 

But Kalmus believes we should never stop fighting.

"The hotter we let it get, the more unsafe we'll be, and the more death and suffering there will be on this planet," Kalmus said. "So no matter how hot it gets, it's worth it to keep fighting as hard as we can to keep it from getting even hotter. That's the bottom line."


Nicole Mortillaro

Senior reporter, science

Based in Toronto, Nicole covers all things science for CBC News. As an amateur astronomer, Nicole can be found looking up at the night sky appreciating the marvels of our universe. She is the editor of the Journal of the Royal Astronomical Society of Canada and the author of several books. In 2021, she won the Kavli Science Journalism Award from the American Association for the Advancement of Science for a Quirks and Quarks audio special on the history and future of Black people in science. You can send her story ideas at

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