The overwhelming growth of climate change science
And the media and communication challenge that it poses.
Scientific publications about climate change have grown dramatically in recent decades, tracking a broader global explosion of scientific research.
By one reckoning, there are now more than 14,000 peer reviewed climate science studies being published per year. That’s according to data from the researcher Danial Khojasteh, who conducted a recent study on the topic while working at the University of New South Wales in Sydney, in Australia.
And even this figure may be conservative — depending on how you tally up the studies, the number could be far larger, other research suggests.
Khojasteh’s study came out early last year in WIREs Climate Change, and used a customized search of the Web of Science database to identify studies. It found that climate science publications grew at a rate of over 10 percent per year between 1990 and 2021. Khojasteh recently sent me updated data through the year 2024, which allowed me to make this chart:
The darker green bars highlight the years when Intergovernmental Panel on Climate Change (IPCC) assessment reports — major moments for taking stock of the results of all of this research — were first released.
Overall, more than 179,000 studies are captured in the graphic. Earlier research, based on a different Web of Science search method, found even more studies through the year 2018 — and a similarly dramatic growth trend.
“It’s just indicative of how much our climate is changing,” said Matthew England, one of Khojasteh’s coauthors and also a researcher at the University of New South Wales.
“Had we addressed the problem 30 or 40 years ago and stabilized our emissions there would still be a lot of science coming out, but it wouldn’t necessarily be the exponential growth this study has revealed,” said England.
The global science boom
The growth of climate science represents just one facet of a broader outpouring of research.
As of 2022, the world was publishing over 3 million works of research per year, according to data compiled by the National Science Foundation based on the Scopus database. This body of global science and engineering research is also growing rapidly, the NSF data suggest.
Khojasteh’s study finds that climate science is growing even faster than global science in general. And depending on how you measure, the figures could be higher than his study suggests.
A study published in 2020 in Nature Climate Change, for instance, found over 40,000 climate science publications in the year 2018 alone (the last year in the data contained in that study). The difference underscores the complexity of trying to comb through a vast and complex literature.
Max Callaghan, a researcher at the Potsdam Institute for Climate Impact Research in Germany who led that study, looked at Khojasteh’s data and commented on the likely reason for the difference. Both studies attempt to combine together searches for specific terms with searches for the content of climate-focused journals. Callaghan said the main difference appears to involve whether one searches for key terms related to climate change just within the titles of scientific studies, or whether you also search their abstracts and keywords.
“There is no perfect query,” Callaghan said. “All of them have to balance sensitivity and specificity, and defining the system boundaries is not trivial.”
“If you restrict the search to titles, then you get the literature that really puts climate change front and center,” Callaghan continued. “But one could argue that if a paper mentions climate change in the abstract, then the paper might still be relevant to our understanding of the literature on climate change.”
Up through 2018, Callaghan’s study also found a rapid increase in annual publications — with the major uptick seeming to start, as in Khojasteh’s data, around the year 2007.
U.S. scientists will likely look at these data with the current political context in mind. With many federal scientists worried about their jobs, and academics concerned about cuts to research funding, will the work, and the publishing, continue at a similar rate?
However, while Khojasteh’s study found that the U.S. is the leading global producer of climate science, it also found that its percentage of the total work published each year is declining. More and more work is being produced internationally.
Taking this into account — and considering the significant time gap between when research is funded, and when it’s published — it’s probably too soon to say what impact recent U.S. changes may have on a global scale.
Unfound stories
Without ignoring this context, I actually came to these data through a different route. I sought them out to aid in thinking about how to improve my own field, climate journalism.
The trouble is that, with so much information being produced, it is not clear how climate journalists should determine what research to cover, or what methods to use (if any) to search through all of the different journals and studies.
As a result, my sense is that a great deal gets missed.
That’s a perspective that Max Boykoff, a professor at the University of Colorado who monitors media coverage of climate change in U.S. papers and more broadly, shared when I sent him these data.
“I think that you’re right to assume that it is a very small and anecdotal selection that gets covered,” Boykoff said in an email.
“Sometimes it may be interesting findings at a moment when something related is going on (e.g. Fires, heatwave, flooding); sometimes it may be effective promotion of the research through press releases, other coverage, social media posts etc; sometimes a well-known author (e.g. James Hansen’s co-authored research this past month),” Boykoff continued.
Let’s be clear: The media are not in the job of comprehensively covering knowledge production in any particular field. The media are also not a substitute for traditional educators.
Still, as a journalist covering science, there’s a good argument for trying to be aware of the broad universe of potential story topics — though how to do this in practice is far from clear.
These studies are not all in Science and Nature, but in journals with names like Geophysical Research Letters, Earth System Science Data, and The Cryosphere (some of my personal favorites). Geophysical Research Letters, alone, published the following studies in the past month or so. I can imagine a science news story about any of them:
As we learned as kids, the Earth rotates around a (tilted) axis in space and the poles are where the axis crosses the planet’s surface. But these poles are projected to shift in location by 12 meters or more by the year 2100 (compared with 1900) due to global ice losses and the resulting shifting of mass around the planet. This could lead to amplified sea level rise in the mid-latitudes.
It’s going to begin to rain more, even potentially at higher elevations, over the Greenland ice sheet as the planet warms. This appears to be another feedback that will accelerate ice losses and raise seas.
The catastrophic flood in southern Brazil’s state of Rio Grande do Sul in 2024 — the result of an apparently unprecedented extreme rainfall event — put over a billion tons of water in normally dry areas, based on satellite measurement techniques.
The challenge of information sifting would likely be even harder at smaller newspapers and publications. As I noted in a prior post, there has been major upheaval at smaller papers and journalists are generally doing more with less (and may not be specializing in climate or environment coverage at all):
Despite the massive loss of newspaper jobs discussed in the above post, major U.S. newspaper coverage of climate change has been growing, based on Boykoff’s data. (There’s also evidence, based on journalist interviews, that coverage is increasing globally.)
However, the growth has not been as rapid at smaller U.S. papers, based on research published last year by Parker Bolstad, a researcher with the U.S. Army, and David Victor, a political scientist at the University of California San Diego.
These smaller papers are usually not covering a great deal of climate science anyway, Victor said in an interview. Rather, their coverage seems to reflect a lot of interest in potentially climate-related disasters occurring in these papers’ regions.
“It’s not academic papers that say X or Y” that smaller papers are covering, Victor said. '“It’s, let’s link climate to wildfires, droughts, farmer productivity, and things like that,” he continued.
However, buried within datasets within buried scientific studies, one often finds datapoints that speak directly to local climate-related risks, measured or projected. See here, for instance (another study that does not seem to have received coverage).
These findings might be very relevant to local communities, if those communities and their journalists were aware of them. When we published this story mapping warming rates all across the U.S. at the Post (based on NOAA data), I remember being struck by how many local follow-on stories resulted, citing the data as they applied to a particular place in the country.
A personal take
As you can see from the above, I come to this from my own experience of writing about climate science for a long time. Indeed, one of the most impactful stories I ever wrote was based on discovering research that otherwise might not have been covered.
In 2019, I traveled to Uruguay to report this story, which (like the prior story) ended up being a centerpiece of the Washington Post’s Pulitzer-winning “2°C: Beyond the Limit” series. From the capital of Montevideo, photo-journalist Carolyn Van Houten and I traveled with a local scientist, Omar Defeo, to the beaches of La Coronilla, close to the border with Brazil. There we would learn about a population of clams that was being assailed by warm ocean waters and experiencing a major decline, in turn imposing hardships upon a community of fishers who had once depended on the species.
Why Uruguay? Why this story?
As the series would reveal, we had used climate datasets to map warming rates across the globe, singling out which regions were warming the fastest. This had revealed a warming hotspot in the ocean off the coasts of Uruguay and Argentina. Seeing this, I had then searched the scientific literature to find out if anyone was studying the consequences. Finally, I came across Defeo’s studies of the clam fishery, which were not in high profile journals like Science or Nature. I do not remember now which studies I found, but this was likely one of them, in the Journal of Coastal Research.
How many other studies like Defeo’s are sitting out there buried in the literature, containing the germ of a major story?
Nonetheless, it remains unclear how the press can — or if it should — sift through such an enormous volume of information. (Hey, somebody raise their hand and mention AI!) It’s easy for me to sit in academia and ask the question, but my colleagues who are filing daily don’t have the time. Covering the politics of climate science in the current moment — scientist funding, scientist employment — is also consuming a major part of their bandwidth.
I don’t have easy answers, but I would suggest that in the press, and for the press, we should be systematically asking the questions.
A note to new subscribers
We’ve had a lot of folks join us since my last major post. Thank you so much for your interest!
Just to give you a sense of what to expect, most weeks I’ll be doing one or two posts. I don’t anticipate more than that, so that’s around the number of emails to expect! Of course, I’m still very much getting used to this platform, so I may change this up.
I’ll do my best to continue to communicate about where I am as I get settled in here.
We need to understand Climate dynamics because of what is a stake. Johann Rockstromm said that this is like fillin the forms to pay taxes. Sometimes it's complicated but we have to do it.
Thank you very much for your post. Greetings from Montevideo
Graph for publications per country quite difficult to view, poor use of repeating colours