Global temperatures are rising at unprecedented rates. Irreversible climate impacts are battering the Earth. And the most ambitious international climate target — halting warming at 1.5 degrees Celsius — is swiftly slipping away.
The U.N. Intergovernmental Panel on Climate Change warned in a dire report Monday that the damaging effects of global warming are no longer a future threat but are already happening. Societies must take immediate — and radical — action to limit the collapse of ecosystems, slow the financial risk of storms, and address intensifying drought and heat waves, the report says.
“It warns that the pace and scale of what has been done so far and current plans are insufficient to tackle climate change,” said IPCC Chair Hoesung Lee. “We are walking when we should be sprinting.”
The report is the final installment in an enormous climate assessment the IPCC has been conducting for more than seven years. The organization has published six major reports as part of that assessment cycle since 2015.
Three installments summarized the current scientific knowledge on the ways the planet is changing, how those changes are affecting human and natural systems, and what societies must do to halt the warming. The overall project also included three special reports on topics including the effects of climate change on land systems, the Earth’s frozen places and the impacts of global warming above 1.5 degrees Celsius.
The final report released Monday synthesizes all of these findings into one conclusive document. It contains no surprises — just a blunt echo of the findings from earlier reports and fundamental conclusion: Climate change is dramatically reshaping the planet, and global action isn’t happening fast enough to stop it.
Climate change is already having widespread effects across every region of the world. Temperatures are rising and extreme weather events are growing more severe, including worsening wildfires, floods, droughts and hurricanes. Sea levels are rising at accelerating rates, and many coastal communities and island nations are facing existential threats from encroaching waters.
Food and water insecurity is on the rise as droughts intensify and agriculture suffers. Infectious diseases are increasing. People around the world are already being displaced by worsening weather and climate extremes.
Human societies have all the tools they need to begin dramatically reducing their carbon emissions, the report notes. Yet greenhouse gases aren’t falling at the rates required to meet the Paris climate targets established in 2015.
The Paris Agreement calls for world nations to keep global warming well below 2 degrees Celsius, while striving for a more ambitious target of 1.5 C. The 1.5 C target requires carbon emissions to drop by about half within the next decade and to hit net zero by 2050. The 2 C target allows only a little extra time: emissions must hit net zero by 2070.
Yet global climate action isn’t proceeding nearly fast enough, and the world is increasingly likely to miss the 1.5 C target — at least temporarily.
‘Survival guide for humanity’
It’s possible that human societies could later lower the Earth’s temperatures back below that threshold by using natural or technological strategies to draw carbon back out of the air. But the higher global temperatures climb before that point, the more difficult it would be to draw them back down.
“It is almost inevitable that we will at least temporarily overshoot 1.5,” said Jim Skea, an energy expert at Imperial College London and co-chair of a IPCC working group, at the launch of a previous report last year.
Monday’s synthesis report echoes that warning. At the rate the world is currently burning carbon, the 1.5 C threshold is likely to arrive in the next decade or so. Even if human societies begin immediately to rapidly reduce greenhouse gas emissions, the world is still likely to overshoot that target.
And even if the world later succeeds in reducing global temperatures back below 1.5 C, some climate damages can’t be undone. Sea-level rise is virtually irreversible once it’s happened, at least for hundreds or thousands of years. The world’s vast ice sheets respond to climate change on very slow timescales and can’t be quickly refrozen once they’ve melted. Plants and animals that go extinct because of climate change are gone forever.
Still, the report stresses that even though some climate impacts are unavoidable, they can be limited with deep and rapid emissions reductions.
The report notes that “adverse impacts and related losses and damages from climate change escalate with every increment of global warming.” That means every little bit of warming that’s avoided can make a difference. Limiting warming to 1.5 degrees was the Paris Agreement’s most ambitious goal — but 1.6 degrees is better than 1.7, and so on.
Limiting warming as close as possible to 1.5 C requires a fundamental overhaul of nearly all aspects of human life, the report notes. Every sector of society must decarbonize as swiftly as possible, including energy, transportation, buildings, industry, land use and agriculture.
Humanity already has all the tools necessary for these radical changes at its disposal, the report’s authors stressed Monday. What’s required now is the political will to make it happen.
Key to those efforts is a willingness on the part of high-income countries to provide the financial resources necessary for all parts of the world to both reduce emissions and adapt to the changes that have already occurred.
The report “tells us that climate change is throwing its hardest punches at the most vulnerable communities, who bear the least responsibility,” said Inger Andersen, executive director of the U.N. Environment Programme.
She pointed to a number of recent climate-related disasters that have devastated vulnerable regions of the world, including Cyclone Freddy, which recently killed hundreds of people in Madagascar, Mozambique and Malawi.
In the past decade, the report grimly notes, human mortality rates from climate disasters like floods, droughts and storms were 15 times higher in highly vulnerable regions of the world, compared to more developed places.
“Money cannot solve everything, but it is critical to narrowing the gap between those who are most vulnerable and those who enjoy greater security,” said Lee, the IPCC chair, adding that three to six times the current amount of financing is required to address the issue.
U.N. Secretary-General António Guterres echoed the calls for increased responsibility on the part of high-income nations in a video message launching the report Monday (see related story).
Developed nations should commit to hitting net-zero emissions by 2040, he said — that’s 10 years earlier than most countries, including the U.S., have committed to. Emerging economies should continue to aim for net zero by 2050, he added.
“The climate time bomb is ticking,” he said.
The new report, he added, can be seen as “a survival guide for humanity.”
IPCC assessment cycles typically conclude every six to seven years. That means the next assessment will probably conclude around 2030.
The latest cycle is coming to a close more than 30 years after the IPCC was established. In that time, scientific certainty around the causes and effects of climate change has solidified. There is no doubt left that human-caused greenhouse gas emissions are warming the planet at unprecedented rates and that rising temperatures have catastrophic effects all over the world.
The biggest remaining uncertainty is how quickly the world will act to stop it.
The changes the Earth endures in the future “will be shaped by the choices we make starting right now,” Lee said.
“So let’s hope we make the right choices, because the ones we make now and in the next few years will reverberate around the world for hundreds, even thousands, of years.”