Countries around the world have delayed curbing emissions for so long that there is no chance of warding off climate disaster over the next 30 years, though there is hope of avoiding even worse fallout down the line, concluded a major United Nations scientific report released Monday.
Now in its sixth cycle, the Intergovernmental Panel on Climate Change (IPCC) released its : rapid and large-scale reductions in greenhouse gas emissions need to happen immediately or limiting warming to 1.5 C or even 2 C will be beyond reach.
Humans have already heated the planet by roughly 1.1 C since the Industrial Revolution triggered the widespread burning of fossil fuels like gasoline, oil and coal.
That has contributed to an already deadly year of extreme weather, where a country’s wealth has proven to be an ineffective buffer against climate-driven events: a heat wave baked British Columbia leading to hundreds of deaths, floods ravaged Germany and China, and wildfires continue to stretch fire crews to their limits from Western Canada and the .
For the first time since the group came together, the scientists linked global climate change with specific extreme weather events.
But that’s only the beginning, warns Xuebin Zhang, a senior research scientist with Environment and Climate Change Canada and the report’s coordinating author on extreme climate events.
Over the next 20 years, rising to 1.5 C means “we should expect more of this hot, extreme weather — more often and more severe,” says Zhang. “It’s simple physics.”
At 2 C, of global warming, the report warns heat extremes would intensify more often and reach “critical tolerance thresholds” for agriculture and health.
At roughly 4,000 pages, the latest IPCC report is not a quick read. We pored over it so you don't have to.
Here are seven things to take away from the world’s premiere group of climate scientists.
1). Human-driven climate change has hit every corner of the planet
Considered the gold standard for climate science going back three decades, the report’s 234 volunteer authors have spent the last several years going through more than 14,000 scientific papers.
But whereas in the past, certain slices of the planet escaped observation due to limits in the deployment of measurement devices, in the sixth report, scientists have collected vast sums of climate data from every corner of the globe.
Combined with powerful modelling tools, it solidifies what science had already established — climate change is not a distant threat, it’s something that’s happening right now.
“The changes and weather climate extremes are occurring everywhere in every climate of the world,” says Zhang.
“Today, we see the changes affecting every region. This was not as clear eight years ago.”
2). Humanity’s best hope is to hit net-zero and fast
The only way to avoid the worst effects of climate change in free fall is for nations to work together to make deep cuts in carbon dioxide emissions and other greenhouse gases like methane and nitrous oxide.
“We need immediate, rapid and sustained reductions,” says John Fyfe, who, as a senior research scientist with Environment and Climate Change Canada specializing in polar climate, was the lead author of the report’s chapter on future global climate.
“If we are able to accomplish that, it’s extremely likely we’ll stay below 2 C and it’s about fifty-fifty that we’ll rise to 1.6 C and then back down to 1.5 C by 2100.”
Global surface temperatures are expected to rise until at least 2050, even under the best emission-reduction scenarios.
That means more intense cyclones thrashing tropical coastlines, more drought, more heavy rain and flooding, and more like the one that recently hit 小蓝视频
By many metrics, there’s no coming back.
The cumulative emissions already dumped into the atmosphere means glacier and polar ice will continue to melt, and seas will rise for hundreds to thousands of years.
“The ocean is a bear, it’s kind of waking up from hibernation,” says Fyfe. “With emission reductions, we can slow down the increase, but we’re not going to stop it.”
Still, there’s no red line, and every reduction in emissions will contribute to a more liveable planet.
3). 1.5 C warming is inevitable and coming faster than we thought, so ‘buckle up’
Even under the best-case scenario, the report finds rising atmospheric temperature will slightly overshoot the 1.5 C mark — the target agreed to in Paris in 2015 and the point where scientists say irreversible damage will be done to the Earth’s climate system.
Passing 1.5 C within the next 20 years moves up the timeline from the previous IPCC report by a decade.
“By 2035, there’s a very good chance we’ll reach 1.5 degrees warming,” says Zhang. “These are rooted in observations. They are statements of fact. This is what we’re seeing.”
“We do need to buckle up — not only for emissions reductions, but to get ourselves to adapt to a new climate. Climate change is here, it’s not going to go away,” he adds.
Last week, 195 nations approved the first instalment of the report, which focuses on the physical science of climate change.
The second and third working groups — which will focus on vulnerabilities and how to adapt to and mitigate the effects of climate change — will release their findings next year.
4). Emission reductions due to COVID-19 temporary
At the beginning of the COVID-19 pandemic, there was a rapid decrease in greenhouse gas and aerosol emissions compared to the previous five years, says Fyfe.
In the short term, modelling conducted by Fyfe showed that such reductions actually led to an increase in temperature. That’s because the cooling effect of aerosols shows up before emissions begin to warm the atmosphere.
When the output of aerosols dropped due to decreased economic activity, so too did its cooling effects.
And while long-term, a reduction in carbon dioxide will theoretically lead to lower rates of warming, Fyfe says the pandemic offered a little more than a blip.
“Carbon dioxide hasn’t gone down in a way we can detect it,” he tells Glacier Media. “The climate system is too noisy.”
As the report put it, “Only sustained emission reductions over decades would have a widespread effect across the climate system.”
5). Canada faces intensified fallout
On average, Canada is warming twice as fast as the rest of the world. That’s partly due to latitude — warming intensifies as you move north, with the most severe effects felt over the Arctic.
“We’ve already seen since the late 1970s, a 40 per cent decrease in arctic sea ice in summertime,” says Fyfe. “There’s no turning back.”
In the report's high-emission scenarios, the expectation is that there will be no see ice in the summertime by as early as 2035.
Fyfe says scientists are also finding the largest changes over land. For the first time in history, the IPCC’s latest report comes with a that allows users to visualize climate modelling at the regional level.
“British Columbia, on average, is warming significantly more than the global average,” says Fyfe. “You’ll see the warming does get larger as you go northward.”
6). Climate 'tipping points' lead to deep uncertainty
As climate science evolves, questions over the sudden collapse of climate, ocean or ecological systems have increasingly piqued the attention of scientists.
The report lays out several Earth system “tipping points” at risk, including a “virtually certain decline” in the Greenland ice sheet as well as carbon frozen in permafrost.
In particular, Fyfe says he and his colleagues have their eye on the longevity of two global circulation systems: the disintegration of the West Antarctic ice sheet and the weakening of the Atlantic Meridional Overturning Circulation (AMOC), a major ocean current system transporting warm surface waters toward the northern Atlantic.
The IPCC report says there will be a “likely mass loss” of the West Antarctic ice sheet “under all scenarios.” But pass 3 C of warming and projections face “deep uncertainty.”
“If the Antarctic ice sheet collapses, it could amount to 15 metres of sea level rise by 2300. And by 2100, it could amount to two-metre sea level rise — it would be traumatic,” says Fyfe. “We would expect storm surges on top of that, extreme sea level rise.”
As for the AMOC — an ocean current made popular in the doomsday film A Day After Tomorrow — the report says it’s very likely weakening but that scientists have medium confidence it won't collapse anytime soon.
Still, Fyfe says a growing body of research has confirmed the major ocean current has collapsed in the past. The consequences would likely lead to deep cooling on both sides of the Atlantic and a massive drying of Europe.
“Of these [warming] scenarios that we investigated, none of them suggest the collapse of the AMOC this century,” says the Canadian climate scientist. “But we want to make clear to policymakers, we can’t rule it out.”
While the IPCC report bases its conclusions on the latest research, its conclusions have been criticized as conservative in the past and new science is painting a more vivid picture every day.
Last week, for example, a study published in Nature Climate Change found evidence that in the course of the last century, the AMOC may have evolved from relatively stable conditions to the edge of a “.”
7). By the time the next report is out, it will be too late
"Climate change is already here."
"The global community is nowhere close to getting things in check."
"Worse is one its way."
Whatever you take away from the latest IPCC report, perhaps the most startling realization is how little time is left to reduce emissions.
If humanity delays reducing emissions until the next IPCC report is out, it will already be too late.
“If we really want to get to 1.5 degrees, it’s still possible, but it’s going to be really, really hard,” says Zhang.
“This kind of emissions reduction is everyone’s business. Every single bit of emissions reductions counts.”
Stefan Labbé is a solutions journalist. That means he covers how people are responding to problems linked to climate change — from housing to energy and everything in between. Have a story idea? Get in touch. Email [email protected].
