What to Expect from the Next Major Global Climate Report

Next month the IPCC will begin releasing its periodic assessment of the state of climate science

By Sara SchonhardtE&E News – Jul 22, 2021

What to Expect from the Next Major Global Climate Report

The Tamarack fire burns along the road in Markleeville, California. Credit: Ty O’Neil Alamy

The Intergovernmental Panel on Climate Change grabbed the world’s attention in 2018 when it released a sobering report that warned—in no uncertain terms—world leaders needed to take drastic and immediate steps to blunt the most catastrophic impacts of global warming.

Policymakers responded with a range of emotion, from denial to outrage. But the message was clear. “It’s like a deafening, piercing smoke alarm going off in the kitchen,” Erik Solheim, executive director of the United Nations Environment Programme, told The Washington Post at the time.

Next month, the Intergovernmental Panel on Climate Change—or IPCC for short—plans to release another report. And again, scientists, lawmakers and activists are bracing themselves for the news.

The report will come three months before world leaders gather in Glasgow, Scotland, to try and figure out a plan to avert the worst effects of climate change. And it’s all but certain the IPCC’s findings will inform that debate.

So, what is the IPCC and what does it do?

One thing it isn’t is a fly-by-night operation. The U.N. group has been around for more than three decades assessing the science behind climate change, projecting what’s to come and offering ways to respond. All with the eyes of the world upon it.

“No other science has been scrutinized as heavily as climate science has in the past 30 years, and that’s thanks to these intergovernmental reports,” said Corinne Le Quéré, research professor of climate change science at the University of East Anglia.

One consistent message among them all: an ever-stronger statement about the human influence on global temperature rise as a consequence of growing greenhouse gases, said Emily Shuckburgh, director of the Cambridge Carbon Neutral Futures Initiative.

On Aug. 9, the IPCC will release the first of four reports under its latest assessment cycle. Here are five things to know about the IPCC, its upcoming report and the politics that surround the effort.


The IPCC consists of government representatives who commission regular environmental reports from academics from around the world. Those experts have produced their assessments on a seven-year cycle since 1988, with special reports in the interim years. The IPCC is currently in its sixth assessment cycle.

The assessments are divided between three working groups, each with a different focus and published on different intervals.

Working Group I is a synthesis of the existing physical science. It answers questions about how much global warming is occurring and where; how warming impacts oceans, sea-level rise and weather pattern changes; and it lays out projections of what we might see in the future. This is the report that will be published in August.

Working Group II, slated for February, focuses on how vulnerable humans and nature are to global warming, the costs of climate impacts or adaptation options. Working Group III, to come in March, will look at options for keeping to global temperature targets and scenarios on renewable energy or carbon capture and storage.


At the end of the cycle there is a final synthesis report. This cycle also will include a task force report on national greenhouse gas inventories.

On Aug. 9, the IPCC will release its summary for policymakers following a series of meetings where it will be discussed, revised and then signed off on.

There are more than 230 authors from 65 countries. Men have historically comprised the majority of these contributors, though that pattern has started to change. Women now make up about 30% of the group. A gender panel and task force is working to bring more women into the process.

The latest assessment will include new advances in science and a better understanding of the human impact on global warming. It will also have an interactive atlas—a novel addition—and five emissions scenarios that will explore the impact of rising emissions.


A certainty statement: Each assessment has included a level of confidence that human activities are responsible for projected warming. The last one in 2013 put that confidence at extremely likely.

Shifting baselines: This assessment will be fed by a new generation of computer models. A report last year, for example, suggested that historical temperature rise has been slightly bigger than previously thought, said Richard Black, a senior associate at the Energy and Climate Intelligence Unit. “What will that turn into about the carbon budget left?” he asked.

Other gases: Given advances in the science around the different greenhouse gases, Working Group I could separate the way they treat carbon dioxide and other long-lived greenhouse gases from methane and other short-lived ones.

Timing: What impact might the report have on upcoming meetings, such as the U.N. General Assembly, the Group of 20 and the climate talks in Glasgow, Scotland? Is the window for achieving the 1.5 degree Celsius temperature limit of the Paris Agreement closing? How quickly? How feasible is it to meet the temperature targets?

Wording: The power of the IPCC is that it’s comprehensive, said Le Quéré. It’s the only report that looks at measurements from the land to the ocean to the stratosphere. It looks at modeling and human experience. That makes the strength of the language and the coherence between the observations all the more important. She said she expects all the new information to come together in a powerful way.


The last major report from Working Group I was published in 2013. What has happened since then is seven years of a warming climate. In that time, nations also signed onto the Paris Agreement, which includes very clear objectives around warming limits of 1.5 C.

It also brings out an important set of challenges about assessing the climate science. Global warming has unfolded at approximately the rate that was projected in the 1990s, Le Quéré said. “But what we see now is that the warming itself, the extreme events, we can see with our own eyes.”

There is also a lot more granular information about the regional distribution of these events and the role of attribution in climate change. In many instances, attribution science has been able to demonstrate scientifically that climate change has increased the probability of extreme weather events, and a lot of that knowledge owes to new observations and modeling.

Working Group I provides a variety of climate projections given an emissions scenario. In the past, it has focused on the most likely climate projections. But his time around, said Le Quéré, governments have asked the IPCC to look at low-probability events that could potentially be very damaging.

That means a lot more explicit information about the risks of extreme climate events, and a lot more regional information as requested by individual governments, she added.


As Black points out, all the governments accept these reports, so they can’t say they didn’t know what the science was saying. The question is: Will they translate that science into action?

Another weedy topic is the carbon budget. While it brings together so much of the science, it also involves all the uncertainty that goes with projection, said Le Quéré.

There also could be issues around procedure because it’s the first time there’s been an attempt to adopt a summary for policymakers on Zoom, said Black. If countries are looking for an excuse to disrupt the whole thing, that’s a good one, he added.

It would be better if all the reports—including Working Group II on impacts and vulnerability and Working Group III on mitigation—were released ahead of climate change talks in November, Shuckburgh said.

But what next month’s report does put forth, she added, will make the risk that climate change poses abundantly clear. It will then be up to leaders to respond.

Reprinted from E&E News with permission from POLITICO, LLC. Copyright 2021. E&E News provides essential news for energy and environment professionals.