Positive feedback cycles—they’re what keeps climatologists up at night. The term describes the way that certain ecological responses to a warming climate can further accelerate warming, creating a feedback cycle that can spiral out of control. Take the billions and billions of tons of methane buried beneath the Arctic permafrost. Methane is about 20 times more potent as a greenhouse gas than carbon dioxide, but fortunately, those vast stores in the Arctic are locked beneath frozen soil, for the most part unable to escape and add to the greenhouse effect. But as the planet—and especially the Arctic—continues to warm, some of that permafrost will melt, potentially leaking methane into the atmosphere and amplifying global warming. And the warmer it gets, the more Arctic permafrost will thaw and the more methane will be released—so on and so on.
But as the planet itself reacts to warming, so will we. People will move away from the coasts as sea level rises, or shift agriculture to the north as the land we farm now becomes too hot and too dry to be productive. Human influence on the planet will shift as we adapt to warming—and we may end up doing even more damage to the Earth than climate change itself.
That’s the warning raised by in a new paper published in the August 6 edition of Conservation Letters. A group of scientists from the green group Conservation International, Princeton University and the University of Massachusetts surveyed how humans might respond to a warmer world—and it adds up to bad news for biodiversity. As the authors write: “The indirect effects of climate change may affect biodiversity and ecosystem services as much or more than the direct effects of climate change alone.” A quick list of what we’re already doing shows what they mean:
- The U.S. has spent billions to support the growth of the corn ethanol industry—partially out of the belief that such first-generation biofuels could replace some oil and cut carbon emissions. But the policy has been linked to losses of grassland habitats in the Conservation Reserve program, while some the fertilizer used to grow that corn eventually washes out in the Gulf of Mexico, feeding dangerous dead zones. And there’s growing doubt that first-generation biofuels cut carbon significantly.
- Hydropower is an existing, utility-scale source of very low-carbon renewable energy. But massive dams can cause ecological problems of their own. China’s massive Three Gorges Dam will be able to produce 22,000 MW of electricity—offsetting countless polluting coal plants—but its 600 sq. km reservoir has threatened 37 endemic plant taxa and 44 endemic fish species, while displacing over 1 million people, who will migrate to new land and put pressure on wildlife there.
- Decreasing water supplies in the American Southwest—linked in part to climate change—has motivated Las Vegas to propose a massive series of pipelines that would bring groundwater from the valleys of eastern Nevada to the booming desert city. The water will come, but the project will likely damage species and ecosystems in the area. The same thing is happening in dry Australia, where proposals for water pipelines conflict with the need to protect the health of river systems.
That’s just what’s happening now. The study team—led by Will Turner at Conservation International—project the impact of future adaption efforts as warming worsens, and the picture isn’t pretty:
- According to climate models, already nutritionally stressed regions like southern Africa may experience substantial declines in corp productivity in just a few decades. As existing farmlands dry up, refugees will seek to colonize wild territories—seriously impacting biodiversity as protected areas are converted into cropland. Even as warming renders some agricultural land unsuitable for farming, however, rising temperatures will open up territory long considered too cold to support crops—and we’ll likely take advantage of that. But much of that new land—like high-elevation areas of East Africa and parts of western Russia—are biodiversity hotspots.
- The study notes that a fifth of the world’s remaining tropical forests lie just a few days walk from human populations that could be forced to move should sea levels rise by 1 m. When people migrate away from the coasts to escape the rising seas, expect them to use those forests for fuel and clear them for farming. That could be devastating for biodiversity—nearly half of the Alliance for Zero Extinction hotspots exist within this zone.
- As warming melts Arctic sea ice, it will also open new shipping lanes and increase the possibility of expanded offshore oil and gas exploration. The far North has been largely untouched by human beings—the presence of heavy shipping and energy infrastructure could wreak havoc on wildlife that will already be coming under threat directly from warmer temperatures. And that’s without a devastating oil spill.
The lesson here isn’t that human beings can’t adapt to climate change without adding to the destruction created by…climate change. It’s that adaptation will only work if it’s well planned for the long-term, and if it takes into account impacts on wildlife and nature as well as on human beings, as the study’s authors write:
The conservation of biodiversity and the amelioration of dangerous climate change are not inherently antithetical. Mitigation and adaptation policies that couple sustainable natural resource management with human development may offer the best possibility for positive ecological and societal outcomes (Ahmad 2009; World Bank 2009). These outcomes depend on considerably more guidance from, and research funding to, the scientific community. Fortunately, maintaining natural habitats, both in parks and working landscapes, is one of the most cost-effective and readily available approaches for mitigating climate change and facilitating human adaptation (Turner et al. 2009; Figure 3): intact marine and forest ecosystems sequester and store carbon and play critical roles in climate regulation; healthy mangroves and reefs dramatically reduce the impact of storm surges on coastal communities; forests, wetlands, and grasslands contribute to ample, clean, consistent water supplies for downstream communities and crops; and wildlands harbor untapped resources, such as the genetic diversity among wild relatives of crops, that can facilitate adaptation to a changing climate. Limiting the losses of biodiversity from climate change mitigation and adaptation actions will be critical to maintaining the ecological services upon which we and all other species depend. Increased research focus on the indirect effects of climate change, coupled with expanded support for biodiversity conservation, will ultimately lead to better policies and programs dealing with global climate change.
Of course, the only problem is that it’s our inability to plan well for the long-term that has led us to the climate crisis—and there’s no evidence that has changed, even as the impacts of warming become harder and harder to deny. Unless the pace of warming suddenly slows—or we can rapidly cut carbon emissions thanks to a political and technological miracle—we may need to beat a few tactical retreats in the face of climate change. How well we plan for that day will decide whether those retreats can help us live to fight another day—or simply lead to greater catastrophe.
