Climate change is dangerous, and it’s happening now. It threatens wildlife and the ecosystems they live in. It will make life harder for billions of people, with the greatest harm hitting the world’s poorest people. It may make some parts of the world uninhabitable for humans, and will almost certainly drive many species to extinction.
But there are a half-dozen other environmental threats that are even worse.
That’s according to a study published this month in Nature, generally considered the world’s most respected scientific journal. According to the study, which lists ten kinds of human-caused environmental damage and ranks them according to the number of wildlife species they now threaten, climate change comes in at just seventh place behind things like logging, farming, and urban development.
In the study, headed up by University of Queensland graduate student Sean Maxwell, researchers studied the threats to 8,868 species around the world currently listed as either Threatened or Near Threatened in the Red List of Threatened Species maintained by the International Union for the Conservation of Nature. Species included in the study ranged from birds, mammals, reptiles, and amphibians to sea anemones, isopod crustaceans, conifers, flowering plants, clams, most types of fish, and jellyfish.
When a species is designated as Threatened or Near-Threatened on the Red List, the listing includes a citation of the types of threats facing causing that species problems. Maxwell and his colleagues tabulated those threats to each of the almost 9,000 species and ranked them in ten large categories, according to the number of species each threat affected.
Here are those big threats, in descending order of harm:
- Overexploitation, including logging, fishing, hunting, and gathering of plants: 6,241 species, 71.8 percent of the total
- Agriculture, including farming, livestock raising, and aquaculture: 5,407 species, 62.2 percent
- Urban development, including residential, industrial-commercial, recreation, and tourism: 3,014 species, 34.7 percent
- Invasion and disease, including invasive species, problematic native species, and introduced genetic material: 2,298 species, 26.5 percent
- Pollution, including air pollution, municipal waste, industrial and agricultural effluent: 1,901 species, 21.9 percent
- System modification of natural ecosystems, including both fires and fire suppression, dams, and a few other things: 1,865 species, 21.5 percent
- Climate change, including drought, habitat change, storms and extreme temperatures: 1,688 species, 19.4 percent
- Human disturbance, including disturbance of affected species when people recreate, work, and wage war: 1,223 species, 14.1 percent
- Transportation, including land, air, and sea: 1,219 species, 14.0 percent
- Energy production, including oil and gas development, coal and uranium mining, and renewable energy development: 913 species, 10.5 percent.
Those percentages don’t total 100 because many of the species examined are endangered by more than one of the threats. (It's probably worth mentioning that by "introduced genetic material," Maxwell et al and the IUCN aren't referring to genetically modified organisms, but rather the threat of rare species hybridizing with more common relatives, as is happening with the endangered California tiger salamander and the invasive barred tiger salamander.)
I did a little digging in the IUCN database, and California’s beleaguered species reflect a mostly similar pattern of threats and their severity, but with climate change coming in in ninth place instead of seventh. Of 877 California species mentioned in the Red List, overexploitation threatens 172, urban development 110, agriculture 105, transportation 40, invasion and disease 40, system modification 38, energy production 36, pollution 24, climate change 23, and human disturbance 16.
And as in the rest of the world, many California species in trouble are beset by more than one threat. The federally Threatened desert tortoise (whose Red List entry was last updated 20 years ago) is hard-hit by disease and the raven, a problematic native; habitat loss to urban development; renewable energy production; and historic losses to collection as pets, a form of overexploitation. The Delta smelt is in trouble due to system modification in the form of water diversions, invasive species, pollution, and climate change. Logging and fire suppression each contribute to declines in the California spotted owl’s population. And so forth.
If you’re accustomed to thinking of climate change as the main peril facing life on earth, the notion that there are several pervasive environmental problems worse than climate change may be surprising. Climate change does imperil a lot of species, but overexploitation imperils more than three times as many. Logging alone, which is responsible for declines in 4,049 species, accounts for more than twice as much harm to wildlife species as climate change in all its forms.
That’s especially sobering given that logging for biomass energy production is often touted as a partial solution to addressing climate change.
Even if you’re not sure you care about things like isopods and sea anemones, the more charismatic species on the list are especially hard-hit by the old-school environmental threats. Three quarters of the mammals, birds, amphibians, reptiles, and plants studied are threatened by overexploitation, agriculture, or both, with invasive species playing an important role in many of those declines.
We must take immediate action to end climate change by drastically limiting our greenhouse gas emissions. But it's ever more important that we don't make things worse for biodiversity in the process.
These figures make even more sense in light of another study, published Tuesday in the related journal Nature Communications, in which study of satellite imagery reveals that 75 percent of the planet's land surface has been changed by human activity, with a nine percent increase between 1993 and 2009. Those changes have been especially intense in places with higher biodiversity, a factor which multiplies the overall harm to wildlife species.
Maxwell and his colleagues grant that their study of IUCN data doesn’t come close to examining every species that’s actually in trouble: they stuck to species in larger groups that have been well-studied by the IUCN. There are other kinds of living things whose threatened-or-not status isn’t nearly as well known, fungi being a very important example. And as mentioned in the case of the desert tortoise, many Red List species’ entries are far enough out of date that the severity of threats may well be understated.
The researchers also grant that climate change will affect more and more species as the years pass, but point out that the same is true of overexploitation, agriculture, and urban development.
So why, with things like logging, industrial fishing, urban sprawl, industrial farming and invasive species still causing the majority of havoc in the environment, are environmental groups and public agencies showing a laser focus on climate change and climate change alone? Maxwell et al suggest that the global citizenry may have tired of facing larger, age-old threats like overfishing that have been going on for centuries with no apparent end in sight. Though some observers have known of the threat of anthropogenic climate change for decades, the issue’s prominence in the public discourse is relatively new, with most of the public learning of the issue only after the release a decade ago of the film An Inconvenient Truth. The issue’s relative novelty may be driving some of the attention.
If that’s really a factor, it’s certainly helped along by the recent fashion among many environmental granting foundations to focus almost entirely on climate change, a sea change that has had many foundation-dependent environmental groups following suit. If most of the grant money is going toward groups’ climate change programs, then any group that relies on grants for much of its funding will have a climate program. As those groups spread the word about climate change, the issue’s prominence and public awareness rises.
That’s all well and good; climate change is indeed a serious issue, posing an increasing threat to species like the pika pictured above, whose mountaintop habitat may disappear as the Sierra Nevada gets warmer. But a near-exclusive focus on climate means that much larger issues of overexploitation, agriculture, and urban development increasingly find themselves pushed to the sidelines. That’s not to say that no environmental groups have been working to combat the ill effects of things like logging, overfishing, invasive species, or unsustainable urban development: many have. But over the last decade the environmental spotlight has increasingly been aimed at climate, with other issues mentioned by mainstream environmental groups mainly when there’s an explicit link to global warming.
This has held true despite a number of studies over the years that indicate loss in biodiversity is likely a greater, more immediate, and more dangerous threat than climate change, as big a problem as the latter is. By providing at least a tentative set of hard numbers, Maxwell et al may have moved that conversation a little further.
Or at least that would be a good development, as focusing entirely on climate to the exclusion of other issues has led to proposals that stand to make the larger threats worse, like logging to fuel biomass power plants, industrial development on wildlife habitat for solar and wind power, or spraying sulfur dioxide into the air in large quantities, in order to address climate change.
From the perspective of Southern California, this is especially true in the realm of utility-scale renewable energy development, which has repeatedly threatened to impede the welfare of wildlife species that are already in trouble. The Sunrise Powerlink transmission line in San Diego County arguably degraded habitat for the Endangered Peninsular bighorn sheep, and allowed construction of the Ocotillo Wind facility in habitat for flat-tailed horned lizards, which are legally unprotected but nonetheless in trouble. Wind installations in the western Mojave are forcing wildlife agencies to consider how to deal with seemingly inevitable fatalities of California condors, while farther east utility-scale solar facilities destroy the habitat of tortoises, fringe-toed lizards and rare desert plants.
For a few years it’s been the official policy of the State of California that the urgency of fighting climate change overrides the importance of following laws protecting wildlife. In one project after another, agencies like the California Energy Commission and county boards of supervisors have declared that the state’s climate goals are an “overriding consideration” of greater importance than protecting species in trouble.
And that can lead us to consider climate change mitigation projects that make larger environmental problems even worse.
Maxwell and his colleagues summarize the risks of focusing entirely on climate change in terms that may well sway even those people who care only about climate change:
Crucially, ensuring that overexploitation and agricultural activities today do not compromise ecosystems tomorrow will help to ameliorate the challenges presented by impending climate change. Healthy ecosystems are better repositories for carbon. They are also more likely to provide the physical connectivity and genetic diversity needed to enable species to adapt to the large shifts in climate expected later this century.
It's absolutely imperative that we take immediate action to end climate change by drastically limiting our greenhouse gas emissions. But as Maxwell et al remind us, it's ever more important that we do so in ways that don't make things worse. If we end climate change by speeding up the earth's ongoing mass extinction, we might end up with an uninhabitable planet anyway.