The following photos and excerpt — highlighting the threats posed to animals and plants by climate change — are drawn from Gary Braasch’s new book Earth Under Fire: How Global Warming Is Changing the World, published by the University of California Press, © 2007. Featuring more than 100 photographs, Earth Under Fire shows species, cultures, and entire ecosystems at risk due to rapid climate change. It tells personal stories of the people whose lives are being disrupted, and delves into the larger implications for businesses, governments, and societies.
As the climate shifts, plant and animal species are beginning to move, each in its own way and at its own pace, in order to stay within unique, evolved envelopes of temperature, moisture, and light. A central tenet of biology and ecology is that living things are inextricably tied to their habitat. As changes proceed, many species will be able to shift their range or change behaviors in response to change. But some will be blocked because they’ve run out of mountain or island, because potentially suitable habitat has been destroyed, or because they can’t move fast enough. What will become of the familiar habitat associations of Earth or the biodiversity and genetic flexibility they contain?
Unfortunately, ecosystems are unlikely to stay intact. “Communities of species do not move together,” according to conservation biologist Thomas Lovejoy. “[Species] move individually at different rates and in different directions.” As climate change intensifies, the life zones and ecological associations familiar to us from introductory biology courses, represented by multicolored bands splashed across world maps, are not going to move in synchrony. Rather, they will deform unevenly as the plants and animals within them react in varying ways. No less than the ice shelves of Antarctica and the permafrost of the Arctic, ecosystems worldwide are rending and disintegrating. With this, the rich biodiversity of Earth, the flow of life that humans rely on, is threatened.
A major factor in this disintegration is the range of speeds at which species adapt to ecosystem changes. Looking back, by reading ice cores, pollen layers, and animal remains, scientists have been able to measure the rate and process of migrations as the glaciers retreated following the last ice age. During those thousands of years, according to a 2005 volume titled Climate Change and Biodiversity, edited by Lovejoy and Lee Hannah, a senior fellow at the Center for Applied Biodiversity Science, a few very rapid atmospheric temperature changes occurred. Those rapid and large climatic changes, notes Brian Huntley in Climate Change and Biodiversity, “triggered substantial numbers of extinctions.” Hardier, or better placed, creatures survived only by embarking on extensive migrations as some habitats shrank or disappeared, while others grew. Adaptation was not an option under such volatile conditions. Adaptation, rather, requires long periods of very slow change, allowing animals to adjust their physical behaviors and characteristics in a process that leads eventually to the evolution of new species.
As is pointed out in Climate Change and Biodiversity, such slow changes — on the order of 1 degree F (0.6 degrees C) over 1,000 years (compared to the 1 degree rise over the last 100 years) — were common in the distant past. In recent millennia, leading up to the present day, the climate has been unusually warm and stable. That stability, however, seems to be gone. This means animals and plants will need to be exceptionally flexible or remarkably mobile if they are to survive. If by flexibility we mean the ability of species to continue to live in a habitat that is changing, Camille Parmesan’s research and analysis indicates that although there are always extraordinary individuals that can withstand stresses, “there is no evidence for [a] change in the absolute climate tolerance of a species.” Unfortunately, species usually go extinct.
Free-living bacteria, plankton, and small insects and plants — parts of the crucial bottom of the food chain — may be able to move (perhaps even evolve) relatively quickly. This is seen in the northward movement of plankton around the British Isles, for example, and in an apparent genetic adaptation to longer summers in a species of eastern North American mosquito. But larger organisms, especially plants and trees that have evolved into narrow ecological niches over thousands of years, may not be able to change fast enough and could well die out.
In a report for the World Wildlife Fund, Jay Malcolm of the University of Toronto’s department of forestry and ecologist Adam Markham estimated that today, global warming is pushing plant species to migrate at a rate 10 times greater than rates recorded from the last glacial retreat. Migration of eastern forest trees appears to have occurred at a rate of more than half a mile a year, according to forest ecologist Louis Pitelka. However, he wrote, this does “not guarantee rapid plant migration in response to future climate change.” For one thing, people have greatly altered landscapes, and many of the resulting blockades and gaps impede migration. Moreover, Pitelka stated, the species whose past migrations we know of are not necessarily representative of the surrounding plant community as a whole. He warned of “the unpleasant prospect that, in the event of rapid climate change, unwanted species — weeds — would be the species that would have little trouble shifting their ranges.”
Investigations of sensitive ecosystems like the tundra and California grasslands show that changing the balance of temperature, CO2, and precipitation reduces diversity. Plants central to the diet of grazing animals and insects may not thrive in the new conditions. In extreme cases, an ecosystem could shift permanently, taking on totally different characteristics, under stress of rapid climate change. It is a well-known ecological process, such as when a lake becomes a bog or when a forest fails to regenerate after a fire or logging.
Aquatic ecologist Marten Scheffer and colleagues warned in 2001 that ecosystems from coral reefs to deserts already have problems from disease and damage from storms or by humans. A severe climate event could rapidly overcome a system’s weakened resilience. Parmesan says in her 2006 paper analyzing 866 studies that “more crucial than any absolute change in timing of a single species is the potential disruption of coordination in timing between the life cycles of predators and their prey, herbivorous insects and their host plants, parasitoids and their host insects, and insect pollinators with flowering plants.” “This,” say Lovejoy and Hannah, “implies that vegetation communities may be torn apart and reassembled in novel ways.”
The implications are enormous. While ecosystems are undergoing great stress, they are more and more important as suppliers of crucial biological services and as repositories of the world’s genetic pool. Think especially of the rich lands of Latin America, like the Amazon, and of Africa, which harbors about one-fifth of all plants, mammals, and birds. In a world where 80 percent of the land is influenced by roads, habitation, river traffic, or agriculture, according to the Human Footprint Project; where overfishing and pollution have reduced many fish populations; where 6.5 billion humans (rising to above 9 billion in this century, if estimates hold) vie for space and returns from the Earth — in such a world the need for the rich benefits of natural landscapes becomes ever more pressing. Yet only about 12 percent of the Earth’s land, and much less of the ocean, is under some kind of protection, and many of the areas that have been set aside are, whether for political or social reasons, too small to support the wildlife and natural features they were intended to protect. Some were founded not on ecological values, but rather for scenic or historical or economic reasons.
As Jeff McNeeley, chief scientist of the World Conservation Union (IUCN), stated at the 2005 Stony Brook World Environmental Forum on parks and reserves, they are not at all separate from human life. “Protected areas mean culture. We have created them.” Although we think of such lands as storehouses of biodiversity, many are crucial to local people for water, building materials, hunting, recreation, and spirituality. Protected areas, in other words, are part of the habitat for human life on Earth, because they help guard the natural world we all rely on. And in a time of global warming, scientists have told the U.N. Convention on Biological Diversity, “genetically diverse populations and species-rich ecosystems have a greater potential to adapt to climate change.”
Perversely, in many cases rapid climate change is knocking the ecological foundations of the parks from under them. If climatic and life zones move outside a park’s constrained boundaries, little hope remains for the associated animals, plants, and watersheds. This includes the hundreds of migratory birds and other animals that rely on specific habitats during their yearly journeys. “We can think of our entire nature reserve and park system as a static network,” wrote Louis Pitelka, “with little flexibility in the face of climate change.” As famed paleontologist Richard Leakey said at the 2005 Stony Brook forum on protected areas, they are “not protected against the ravages of climate change.”
The list of famed parks and World Heritage Sites under great pressure from human development, and now also affected by climate change, reads like an eco-tourist’s dream itinerary: the Everglades and West Bengal’s Sundarbans mangrove forest, the Great Barrier Reef and Florida Keys, the Monteverde cloud forest of Costa Rica and the Daintree rainforest of northern Queensland, Glacier National Park and Mount Kilimanjaro, Nepal’s Sagarmatha National Park, the Farallon Islands, Alaska’s Arctic National Wildlife Refuge, and the Antarctic Peninsula, to name just a few.
Even natural paradises that have just been discovered and are free of direct human damage are menaced by climate change. Just weeks after expeditions from Kew Gardens in London and Conservation International announced discovery of a new genus of palm tree and previously unknown species of insects, birds, frogs, and a marsupial tree kangaroo in the highlands of New Guinea, another researcher said weather records showed the place was warming 20 times faster than previously known. We may think that designating such natural marvels as protected areas is enough. But in reality, these areas’ very isolation makes them highly vulnerable.
As Thomas Lovejoy put it at the protected-area forum, “We have to stop thinking we can protect a few postage stamps with fences around them and use up all the rest.” The lands set aside in national parks and reserves, along with their ecosystem services to us, will deteriorate without strong interconnections with the surrounding land, water, and people who care about them. The reverse is likely true as well: the surrounding land, water, and people will deteriorate if the protected areas are lost. We need to protect biodiversity and whole ecosystems not for their sake alone, but also to help us survive climate change.
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