Climate change is already altering the planet, and the world will see catastrophic and unavoidable impacts over the coming decades, the Intergovernmental Panel on Climate Change said in a wide-reaching report released Monday. The warming we’ve already seen has pushed many of the planet’s ecosystems toward points that scientists on a press call Sunday repeatedly called the “hard limits” of human adaptation — the physical inability for society to adjust any further to oncoming changes in our world.
“I have seen many scientific reports in my time, but nothing like this,” António Guterres, the UN secretary general, said. “Today’s IPCC report is an atlas of human suffering and a damning indictment of failed climate leadership.”
The world has already warmed 1.09 degrees Celsius (1.96 degrees Fahrenheit) above preindustrial levels, thanks to our addiction to fossil fuels. Some of the things we’re already seeing with our current levels of warming, the report finds, include:
- diseases migrating into new areas
- extinctions of species across the world
- local populations of plants and animals dying off or moving, which irrevocably alters local ecosystems
- mass die-offs of trees, plants, and mammals thanks to droughts and heat waves
- the beginning of the collapse of major food systems
- the transformation of former carbon sinks, like the Amazon rainforest and permafrost in the Arctic, into greenhouse gas emitters.
“We’re seeing adverse impacts being much more widespread and being much more negative than expected in prior reports,” said Camille Parmesan, an ecologist at the University of Texas at Austin and one of the lead authors of one of the report’s chapters, during a press briefing Sunday.
The Paris Agreement set out goals of keeping warming under 2 degrees Celsius (3.6 degrees Fahrenheit) and a stricter goal of limiting warming to 1.5 degrees Celsius (2.7 degrees Fahrenheit). The world is already on track to meet the 1.5 degree target, which will bring with it an enormous amount of change. And while humans can still turn the tide and bring warming back down, even overshooting these targets by just a little will bring “irreversible” impacts to the world, as permafrost melts, heatwaves and droughts increase, and ecosystems are forever altered. The small 0.5 degrees Celsius difference between the 1.5 and 2 degree targets, for instance, means that another 65 million people would experience “exceptionally” extreme heatwaves each year.
“This [report] has opened up a whole new realm of understanding of what the impacts of overshoot might entail,” Parmesan said.
This more than 2,000-page report, written by 270 scientists who reviewed tens of thousands of separate studies, comes on the heels of another IPCC report released last summer. Both are exhaustive and comprehensive overviews of the body of science around climate change. Last summer’s report dealt with the physics of climate change — how warming is altering the world and increasing the risks of droughts, fires, storms and floods — while this report focuses on the impacts of that change on ecosystems, wildlife, and human society. Think of this update as the next instalment in a thorough scientific series: the Empire Strikes Back of just how serious the planetary situation is.
The news from this sequel isn’t good, and there are all sorts of terrible examples of what is happening and what’s projected to happen as the planet keeps warming. Half of the world’s living organisms are currently moving habitat as a result of climate change, disrupting ecosystems around the world. Half of the world’s human population also faces water scarcity at least part of the year. Food systems are at major risk: Reaching that 1.5-degree target, which is increasingly likely under current trajectories, would render about 8% of the world’s farmland unusable. And in a worse-case scenario, up to 9 million additional people could die from exposure to climate-related illness by the end of the century.
The IPCC last released a set of reports like these in 2014. Since then, the attribution science behind climate change has made leaps and bounds, meaning that we now know a lot more about how specifically climate change is tied to these impacts than the last time it was released. Timing matters, too: The next time a comprehensive review will come out will likely be in another five to seven years. We’re on such a tight schedule that it may be too late to influence policy the next time a report like this is released.
But there’s still a chance of preventing the worst impacts, the report finds. Mitigation is going to be especially important in the coming decades, and leaders need to be increasingly aware of how climate change will affect their regions and understand that things are going to only get worse — especially for vulnerable populations.
“If regions are not prepared, then people die that don’t need to,” Kristie Ebi, an epidemiologist at the University of Washington and one of the lead authors of one of the report’s chapters, said during the press briefing, referencing the heat wave that hit the Pacific Northwest last year and killed hundreds of people. “Nobody needs to die in a heat wave. And it’s critically important to start looking at these increases in extreme weather and climate events, looking at the people in harm’s way, mostly the poor and the marginalised, and making sure that efforts are undertaken to protect and promote health and wellbeing in those communities. If we don’t, then you saw what the risks look like into the future.”
Throwing our all at reversing our fossil fuel use — something the world looks less and less likely to get on track to do — will be crucial.
“There isn’t a silver bullet that’s gonna solve our greenhouse gas emissions,” said Ebi. “It’s important to understand that every action matters.”