The International Union for Conservation of Nature keeps what it calls a Red List of species that are threatened with extinction due to habitat loss or exploitation, such as overfishing. But a new study led by researchers at Oregon State University suggests another reason some wildlife might be at risk: climate change.
The scientists analyzed nearly 71,000 wild animal species — from corals to reptiles, insects to mammals — assessed by the IUCN Red List and categorized them according to climate-related threats they face, such as drought or temperature extremes. The researchers found that more than 3,500 animal species are threatened by climate change, especially invertebrates like spiders, corals and jellyfish. The study also warns that mass mortality events linked to climate change, such as the marine heat wave in the Pacific Ocean that killed off 4 million common murres a decade ago, will “greatly accelerate” with rising global temperatures.
Joining us to discuss the study’s findings is co-author Jillian Gregg, a senior instructor at OSU’s College of Agricultural Sciences and the founder and CEO of Terrestrial Ecosystems Research Associates.
Dave Miller: This is Think Out Loud on OPB. I’m Dave Miller. The International Union for Conservation of Nature [IUCN] keeps what it calls a Red List of species that are threatened with extinction. The list focuses on habitat loss, which we just heard about, and things like overfishing. But a new study led by researchers at Oregon State University aimed to quantify the impact that climate change is having on these species as well. The scientists analyzed more than 70,000 wild animal species – from corals and reptiles to insects and mammals – and categorized them according to climate-related threats. They found that more than 3,500 of those species alone are threatened by climate change.
Jillian Gregg is one of the co-authors of the paper. She is a senior instructor at OSU, a member of faculty there. She’s also the founder and CEO of Terrestrial Ecosystems Research Associates. She joins me now. It’s great to have you on Think Out Loud.
Jillian Gregg: Well, thanks for having me.
Miller: What was the big question that motivated you in this work?
Gregg: The big question that we had, we knew that wild animals are being harmed by climate change and many people just don’t realize how serious the problem was. So animals can’t vote or speak for themselves, but they’re showing us that the planet is under stress. So when animals start disappearing or dying in large numbers, it’s a warning sign for all of us, like the canary in the coal mine. And yeah, we really wanted to get the word out that climate change is no longer just about the future, but it’s impacting wildlife today.
Miller: The press release for this new paper says that at least one quarter of the species on this list, in six different classes, are threatened by climate change. What are some specific examples?
Gregg: Well, I came up with some numbers, cause it’s over 3,000 species. Over 3,500 species are being impacted. So that can include nearly 600 different types of fish, over 250 types of corals, over 500 birds, nearly 600 insects, over 200 reptiles, nearly 700 amphibians, 237 mammal species. Some popular mammal species – it’s out of over 3,500 animals – [include] cheetahs, giant panda, black howler monkeys, blue whales, six species of seals, prairie dogs, zebras, six species of gazelle, eastern and western gorillas, three species of elephants. And yeah, the list goes on.
Miller: What are specific ways that climate change is affecting any particular species?
Gregg: Well, historically, when we think of species loss, we think of what you were talking about before, that it’s driven mainly by habitat destruction and overexploitation. But in 2004, the Red List started to include climate change impacts, so altering temperatures, altering precipitation, changes in seasonal cycles, floods, storms, droughts and ocean acidifications. And these things all in turn disrupt animal reproduction, migration, survival. So they’re direct impacts on organisms.
Miller: How did you do this analysis?
Gregg: We use the IUCN Red List. That’s an amazing list. They began in 1964 keeping track of all the endangered species. They identified the species that are in need of targeted recovery efforts. They identify key habitats and sites that need to be protected. So they use population data, geographic range and extinction probability assessments to determine which species are most at risk of extinction and why.
Miller: Is there always a bright line between habitat loss and climate change? I mean, I guess I’m thinking about if you’re a polar bear, it seems like they’re directly related. I’m wondering how you tease that out.
Gregg: Yeah, that’s in the details of the IUCN Red List and how they tease us apart. But most species, it’s documented that they’re having all of the above, maybe they’re being exploited, overexploited, maybe they have lost their habitat. And also, climate change is impacting them at the same time.
But you’re referring to the fact that if all of the ice is melting, that is impacting their habitat loss. I think habitat loss generally, if it’s not related to climate change, is more that humans went in and built a city or took the whole forest away, whereas the melting icebergs would be more related to a climate change impact.
Miller: It was notable that when you gave us some overall numbers of animals that are included here – 600 fish, 250 species of coral, 200 reptiles … then, when you got into some of the most well known animals, it was mammals. What classes of animals do you think are not getting enough attention in these conversations?
Gregg: Well, yeah, I think it’s usually small and I’m not really sure.
Miller: I guess I’m just wondering about the extent to which we’re paying attention to insects, to invertebrates, to creepy-crawlies, as opposed to what humans think of as cute and fuzzies?
Gregg: Yeah, that’s certainly the case. Certainly, there’s many, many species of animals that are not even documented yet. So we need to make sure to document all of the species and then we also need to make sure that the species that are documented or assessed to whether they’re in decline or not. And all of this takes time and effort. So it is true that there is more funding for examining species that are more obvious to us.
Miller: Maybe this is an example of my, I don’t know, unhelpful fatalism after years of seeing just increasingly bad climate news. But I have to admit when I saw the headline in an OSU article about the study, that thousands of species are threatened by climate change, one of my thoughts was “only thousands?” But it does make you wonder – and you’re getting to this, but I’d like to get your thoughts on this – how complete you think that number is?
Gregg: Oh, it’s only the beginning, the tip of the iceberg. Yeah, it’s just what has been assessed. What’s on the Red List is only 5% of all species that are described. All species are not even described and all species on the Red List have not necessarily been assessed for whether they’re responding to climate change.
Miller: In other words, we can perhaps add at least a zero, maybe more to that list.
Gregg: Yeah, I would say so.
Miller: In recent years, there have been mass mortality events where we’ve seen die-offs of individual species linked to climate change. The marine heatwave in the Pacific Ocean that killed millions of marine birds about 10 years ago is one example. How do you think these kinds of mass mortality events will be affected by human behavior in the coming years?
Gregg: Well, as climate change increases, I mean, we’re only getting warmer temperatures and more extreme temperatures, more floods, more droughts. And what is well documented, as of late, is looking at the extreme events and assessing whether climate change has made them more extreme or not. And there’s a very nice database, or an interactive map, that’s put out by the Carbon Brief, where they look at all different climate events as they happen and assess whether they were due to humans or not. And what would be a fantastic addition to that map is if, in addition to assessing whether the extreme event was due to humans or not, then if it was due to humans, also assess what the impacts were on the die-offs, these widespread die-offs of plants and animals. So, what the actual impacts are gonna be.
Miller: What would that provide in terms of data for scientists that we don’t currently have?
Gregg: It would provide nice housing for being able to access all the different things. So you could put in there and say, “well, we just want to know, what are the impacts of temperatures?” And then you see which species were responding to temperature only, what’s happening with floods or what’s happening with drought. And then you would be able to see the global distribution.
So right now, people are well aware maybe of the example that you just gave, or even for the Pacific Northwest heat wave of 2021 [which] coincided with these really low tides. And that caused extreme lethal temperatures of over 50 °C that led to widespread die-off of the barnacles, mussels, clams, oysters. Billions of marine invertebrates were killed, but we’re more aware of that in this area because we were part of this heat wave. So if there was a clearinghouse for all different animal losses throughout the world, that would be a huge benefit.
Miller: What does it mean to you to be doing this work, to be releasing this study now, at a time when the federal government is not interested in funding the prevention of the study of or even just acknowledging the reality of climate change?
Gregg: That is completely bizarre. Yeah, in fact, along with all of the federal job cuts, a lot of the climate change funding has been canceled. One specific example of this is all the funding for climate smart agriculture. We actually had a partial funding source that was from a private individual, so it may be, over the next four years, we will be needing to look more towards private sources than for federal funding.
Miller: Although, as we’ve heard in many venues, but probably nowhere more so than scientific research, it does not seem like there’s enough money from private individuals to go anywhere close to the amount of federal money that has been spent in the past and is being cut now in terms of basic science.
Jillian Gregg, thanks very much for joining us.
Gregg: OK, thank you.
Miller: Jillian Gregg is the founder and CEO of Terrestrial Ecosystems Research Associates and one of the co-authors of this new study led by researchers at OSU.
Note: The following transcript was transcribed digitally and validated for accuracy, readability and formatting by an OPB volunteer.
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