Species? Climate? Cost? Ambitious goal means trade-offs

doi:10.1126/science.371.6529.555

GSTDTAP > 气候变化

DOI	10.1126/science.371.6529.555
	Species? Climate? Cost? Ambitious goal means trade-offs
	Erik Stokstad
	2021-02-05
发表期刊	Science
出版年	2021
英文摘要	President Joe Biden last week unveiled an ambitious conservation goal, unprecedented for the United States: conserving 30% of the country's lands and waters by 2030, which would require more than doubling the area of public and private holdings under heightened protections. Conservation scientists welcomed the so-called 30-by-30 goal, announced in an executive order released 27 January. “The ambition is fantastic,” says ecologist Joshua Tewksbury, interim executive director of the nonprofit Future Earth. But Biden's order also raises a thorny practical question: Which swaths of land and sea should be the top targets for enhanced protection or management? The order says the effort should aim for a number of outcomes, including preserving biodiversity, curbing climate change, and even creating jobs and promoting environmental justice. But researchers warn that difficult trade-offs lie ahead, because few chunks of territory can provide all of the desired benefits. “The balancing act [will be] the hardest part of this work,” Tewksbury says. Reaching the 30% goal could require extending protection to vast expanses of land and sea, depending on how officials define “protected.” Only about 12% of U.S. land is already in wilderness areas, wildlife refuges, national parks, and other reserves with strong protection, according to the U.S. Geological Survey. Much is in Alaska; just 7.5% of the lower 48 states is highly protected. (An additional 18% of all U.S. land has weaker protection that allows certain uses, such as logging or mining.) At sea, the country is much closer to the goal: Some 26% of coastal waters is protected to some degree within sanctuaries, national marine monuments, or other entities. Last week, researchers at Boston University and the Nature Conservancy released a paper that maps and compares scenarios for reaching the 30% goal in the coterminous United States (which excludes Hawaii and Alaska). The scenarios examine trade-offs among four goals: minimizing cost, protecting climate-resilient landscapes, protecting species, and curbing carbon emissions. Making cost the top priority led to expansive new protection in the western plains, where land is cheaper. But because most of the added land supports relatively few threatened species, the scheme would fall short on that measure. The least cost scenario also protected relatively little land that absorbs or stores climate warming gases such as carbon dioxide or methane. Another scenario, which emphasized protecting resilient and connected landscapes, cost twice as much. It preserved areas across most of the country except deserts and the corn belt. A third vision, focused on preventing the loss of grasslands and forests that store carbon, delivered the most climate benefit, but cost three times as much. It also produced a patchwork of protected forests in the southeast that lacked connections, reducing their value for preserving biodiversity. A final scenario, which protected species across the country but especially in the south, covered the greatest range of ecosystems. It cost four times as much and provided fewer climate benefits. Overall, the analysis found that just 2% of lands scored highly on all four measures. Observers say Biden could make rapid progress and contain costs by focusing on territory already owned by the federal government. “We can make really huge gains on Forest Service and Bureau of Land Management lands,” says Jacob Malcom, a conservation biologist with Defenders of Wildlife. That could mean reducing logging, mining, drilling, and grazing. “There will be vested interests who are not happy about that,” Malcom notes. “So I don't want to make it seem like it's going to be easy.” Fishing associations, for example, have already criticized proposals to ban commercial fishing in 30% of U.S. waters. “Thirty-by-thirty is a campaign slogan, not a scientific proposal,” Robert Vanasse, executive director of Saving Seafood, wrote last year. Rebecca Shaw, chief scientist of the World Wildlife Fund, notes the Biden order does not exclude human uses of natural resources. “It's not protect, it's conserve,” she says. “And that means getting creative.” Ending subsidy programs for fossil fuel extraction, for example, and boosting programs that pay farmers to conserve lands could help reach the goal. Other assistance could come from a recent federal law that more than doubles spending—to some $900 million per year—on the Land and Water Conservation Fund, which can help states and local governments buy land. The Biden administration's plans should become clearer by May, when federal agencies must outline their strategies for reaching the 30-by-30 goal. Other nations will be watching, notes Charles Barber, a senior biodiversity adviser at the World Resources Institute. He notes that many countries are pushing for the United Nations to adopt a global 30-by-30 goal, and “the credibility of the U.S. as an international leader will depend a lot on what people see the United States doing at home.”
领域	气候变化 ; 资源环境
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文献类型	期刊论文
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/314033
专题	气候变化资源环境科学
推荐引用方式 GB/T 7714	Erik Stokstad. Species? Climate? Cost? Ambitious goal means trade-offs[J]. Science,2021.
APA	Erik Stokstad.(2021).Species? Climate? Cost? Ambitious goal means trade-offs.Science.
MLA	Erik Stokstad."Species? Climate? Cost? Ambitious goal means trade-offs".Science (2021).