Look at the websites of major environmental organizations and you might be persuaded that climate change is the only real environmental issue we face. A majority of American environmentalists have adopted climate change as their main cause, and it's easy to understand why: when scientists agree that our planet is likely to be 5° to 10° F hotter by year 2100, that'll get your attention.

Climate change is a serious issue, but a couple of recent studies remind us that it may not be the biggest threat to life on Earth as we know it. It may in fact be essentially a symptom of a broader problem, one which hasn't gotten nearly as much attention from either green groups or the environmentally oriented press. What's the issue? Loss of biodiversity, also known as extinction. And ignoring it to focus on climate change can have dire consequences, especially in the California desert.

In the interests of full disclosure, I should say that for the last few months I've been working to launch a non-profit, Desert Biodiversity, to promote and defend the biological diversity of North America's deserts. I'm not an objective observer here. The deserts of North America are an uncharted biodiversity hotspot, largely intact and with a surprising wealth of species: think "rainforests without rain." And they're ground zero for industrial renewable energy development propelled by national concern about climate change. We have here a situation in which proponents of a solution to a huge environmental problem may actually be worsening a bigger problem.

Despite my non-disinterested point of view, I think it's arguable that the collapse in biodiversity has deeper roots. Even if we transform our society to a carbon-neutral one, as long as our numbers continue to swell and our demand for comforts continues, other species will pay the ultimate price. As we convert more and more of the planet to resources for our own use, we deprive other species of the habitat they need to survive. Most biologists agree that species are going extinct at at least 100 times the "background rate," perhaps more like 1,000. As one species after another dies out, the total biological diversity of the planet dwindles, and the resilience of the ecosystems on which we depend suffers. The pace of extinction hastens and the web of life unravels even faster.

A recent study out of UC Santa Barbara lends support to the idea that biodiversity and the resilience of the environment are deeply intertwined. The study, published in Nature on May 2, found that ecosystems that had lost species suffered losses in plant productivity. (This is important: plant productivity -- the use of sunlight to turn water and carbon dioxide into organic matter - is the basis of most life on Earth.) Researchers found that the greater the loss of plant species in an ecosystem, the lower plant productivity became. As postdoctoral fellow Jarret Byrnes said in a press release from UCSB's National Center for Ecological Analysis and Synthesis (NCEAS),

"For the past 15 years, ecologists have built a rich understanding of the consequences of humans driving species extinct. What we didn't know before this paper is whether those impacts of species loss rank up there with those from the major drivers of environmental change. Our work shows that, indeed, the impacts of species loss look to be on par with many kinds of human-driven environmental change."

In other words, according to NCEAS, loss in biodiversity poses just as big a threat to the planet as climate change or pollution. NCEAS isn't alone in this assessment. In January, biodiversity researchers from around the world convened in Copenhagen to coordinate a United Nations response to the extinction crisis. In a statement released after that meeting, Carsten Rahbek -- Director of the Center for Macroecology, Evolution and Climate at the University of Copenhagen -- said "The biodiversity crisis is probably a greater threat than global climate change to the stability and prosperous future of mankind on Earth."

The sober-sided report out of Copenhagen speculates that if things keep going the way they have been, the current wave of extinctions will reach mass extinction proportions -- with at least 50% of terrestrial animal species wiped out -- by 2250 AD or so. Many scientists find that assessment optimistic.

This isn't news. The greater environmental world of advocacy groups and agencies and scientists knew the gravity of the current wave of extinctions, and agreed that it was a crisis worth immediate action, by 1992. That's when the much-lauded "Earth Summit," formally known as the United Nations Conference on Environment and Development (UNCED), took place in Rio de Janeiro. Over the course of the week-long meeting, representatives of governments and NGOs hammered out two important legally binding agreements that were then distributed for signatures. One was the UN Framework Convention on Climate Change, a precursor to the Kyoto Protocol. The other was the Convention on Biological Diversity.

Both were given more or less equal weight by those assembled, but the Convention on Biological Diversity actually attracted more attention at the time, even from the conspiracy-minded anti-environmental crowd, who campaigned against UN Biosphere Reserves the way they do now against the jackbooted Carbon Tax.

Something changed in the intervening 20 years, though. Check out this Google 'Ngram" charting the relative frequencies of the phrases "climate change" and "biodiversity" in English-language books from 1990 to 2008. Both phrases were mentioned with increasing frequency in the early 1990s, with "biodiversity" pulling ahead in the months after UNCED. Then, in 2005 -- a few months before the release of An Inconvenient Truth -- "climate change" started getting more attention, and mentions of biodiversity actually began to decrease for the first time since the 1980s.

This despite 2010 being the year in which some of the biodiversity commitments made 18 years earlier at UNCED started to come to fruition. 2010 was declared the UN's International Year of Biodiversity, a kickoff to the United Nations Decade on Biodiversity running from 2011 to 2020. In April, 90 governments -- working under the auspices of the UN -- finally established the Intergovernmental Platform on Biodiversity and Ecosystem Services (IBPES), a global scientific panel that will work to promote biodiversity the same way the IPCC works on climate change issues.

Though official policy is starting, after 20 years, to address UNCED's 20-year-old commitment to address the threats to biodiversity, American environmentalists lag behind. Read the websites and publications of the largest mainstream groups and you'll find some mention of biodiversity as an issue here and there, while every group seems to have a climate change campaign -- even the wilderness organizations, which a person might expect to be biodiversity focused. Of national groups, only the Center for Biological Diversity has an explicit emphasis on diversity and extinction regardless of cause. On the "About us" page of the venerable group Defenders of Wildlife, which you might expect would be generally oriented toward protection of biodiversity in the animal realm, Defenders explicitly lists three topics as "issues we care about most": climate change, renewable energy, and "living with wildlife." Protection of species and their habitat are listed as topics of interest, but they're relegated to the "you may also be interested in" section. The Natural Resources Defense Council has a reasonably robust species protection component, and on NRDC's priority issues page that campaign is listed fourth, with climate change listed as NRDC's first two priorities. The Sierra Club's Goals page -- which actually contains the Goals of the Club's "Climate Recovery Partnership," apparently synonymous with the goals of the Club -- lists the following campaigns: Beyond Coal, Beyond Oil, Beyond Natural Gas, Protecting America's Waters, Resilient Habitats, and a youth outreach program. The Resilient Habitats campaign is a biodiversity initiative, but it's framed entirely in terms of climate change. Only the "America's Waters" campaign isn't centered on climate as an issue, addressing habitat, pollution, and other traditional environmental concerns.

There's nothing wrong with working on biodiversity issues in the context of climate change. Climate change is a major threat to biodiversity. Climate change alters habitats, threatens species with narrow temperature tolerances, interferes with migration timing and reproductive cycles, and in general just screws up wildlife species' ability to make a living.

By the same token, it would make sense for climate groups to operate biodiversity campaigns, as loss in biodiversity greatly complicates the effects of climate change -- from logged primeval forests that no longer sequester carbon to loss of pollinators making it even harder to grow food in a warmer world to the hundred other ways in which losing diverse ecosystems worsens the effects of global change. But you don't see climate groups starting biodiversity programs.

Quite the opposite, especially in the California deserts, where the threat of climate change is being used as a reason to bulldoze habitat that is vital to endangered, threatened and rare species. Though the popular conception of the desert is of a barren place unpopulated by wildlife, California's deserts are in fact a biodiversity treasure, with varied topography and climate breeding new species that continue to be discovered at a surprising rate. Pick a square-mile section of the California desert at random and you run about a 75 percent chance of finding at least one sensitive plant species there, usually more. And yet the once green-leaning Governor of California has adopted bulldozing the desert for renewable energy development as official Administration policy, and the California Energy Commission routinely grants permits to desert energy development despite irremediable impacts to desert biodiversity, citing the need for non-carbon energy as an "overriding consideration" more important than trying to forestall the coming mass extinction.

Until environmentalists catch up with the science that seems to be passing them by, this is unlikely to change anytime soon. In the meantime, May 22 is International Biodiversity Day: you might go out and enjoy some of our remaining biological diversity while you still can.

Chris Clarke is an environmental writer of two decades standing. Director of Desert Biodiversity, he writes from Palm Springs regularly at his acclaimed blog Coyote Crossing and comments on desert issues on KCET weekly. Read his recent posts here.