Climate change and animals.

• Author: Hsiung, Wayne

Climate change is already having adverse effects on animal life, and those effects are likely to prove devastating in the future. Nonetheless, the relevant harms to animals have yet to become a serious part of the analysis of climate change policy. Even if animals and species are valued solely by reference to human preference, consideration of animal welfare dramatically increases the argument for aggressive responses to climate change. We estimate that, even under conservative assumptions about valuation, losses to nonhuman life might run into the hundreds of billions of dollars annually. Whatever the precise figure, the general conclusion is clear: an appreciation of the likely loss of animal life leads to a massive increase in the assessment of the overall damage and cost of climate change.

INTRODUCTION I. SOME EFFECTS OF CLIMATE CHANGE II. ACCOUNTING FORANIMALS A. Intrinsic and Instrumental Value B. Monetary Valuation III. THE (ANIMAL) COSTS OF CLIMATE CHANGE A. Extinctions B. Three Assumptions C. Estimates 1. Use Value Estimates 2. Use Value Objections 3. Nonuse Value a. Contingent Valuation: Foundations b. Contingent Value: Estimates c. Revealed Preference D. Summary and Caveats CONCLUSION INTRODUCTION

Polar bears depend heavily on Arctic sea ice for their survival. When sea ice breaks up and drifts as a result of polar warming, the bears must move northward to find stable platforms. Hunting becomes more difficult, because the bears are rarely successful in finding food on open water. Pregnant females, who must leave the ice to find their preferred terrestrial den areas, are forced to swim great distances and to fast for long periods, as the ice drifts farther from land. Even if pregnancy is successful, the bear cubs--raised in suboptimal habitats with malnourished mothers--are most unlikely to flourish.

Harlequin frogs are a vibrantly colorful and active genus of frog in Central and South America. They suffered widespread extinction in the twentieth century--67% of 110 species--despite attempts at habitat protection. The culprit is apparently a pathogenic outbreak triggered by climate change. The chytrid fungus grows on the frogs' moist skin and eats away at their epidermis and teeth, before ultimately killing them. Tellingly, approximately 80% of the lost harlequin species disappeared after an unusually warm preceding year. (1)

The British ring ouzel, a shy species of thrush with a high chirping call, has been in decline for most of the last hundred years. Up to 58% of the population disappeared from 1988 through 1999, and as few as 6000 mating pairs are left. High temperatures and precipitation in the preceding year have been linked to subsequent declines in the ring ouzel population. Biologists speculate that temperature and rainfall extremes have led to a decrease in food availability. (2)

These are but three examples of the potential impact of anthropogenic climate change on animal life and welfare. While the current effects of climate change on human beings are disputed, (3) there is little question that the impact on animal life is already substantial. (4) Projections into the future are much bleaker. One particularly dramatic study, published in Nature in 2004, suggests that 15% to 37% of all species--potentially millions--could be committed to extinction by 2050 as a result of anthropogenic climate change. (5)

Yet conventional economic analysis of climate change has virtually ignored these effects on nonhuman life. (6) A highly influential study by economists William Nordhaus and Joseph Boyer treats the welfare cost of species loss as too small or uncertain to be accurately quantified. (7) Bjorn Lomborg's well-known analysis of the problem simply fails to discuss animals at all. (8) Nicholas Stern's massive study makes little effort to come to terms with the effects of climate change on animals, notwithstanding its emphasis on the omissions in previous treatments. (9) Richard Tol recognizes the impact of climate change on natural ecosystems, but arbitrarily stipulates a fixed $50 per person willingness to pay to "protect natural habitats" regardless of the anticipated impact. (10)

The consequence of these omissions and stipulations is almost certainly to underestimate, by a large margin, the monetary cost of climate change. Consider the fact that in 2004 alone, federal, state, and local governments in the United States spent over $1.4 billion to protect around 1340 entities (a mere thousandth of the threatened loss from climate change) under the Endangered Species Act (ESA), and expenditures have increased dramatically in recent years as more entities have been added to the endangered list. (11) Moreover, an expenditure measure may well underestimate the true value of endangered species protection, since most of the costs of the ESA are compliance and opportunity costs, stemming from the inability of landowners or governments to engage in otherwise valuable projects. One study estimates that the true annual cost of the ESA (and thus its implied minimum value) is six times greater than nominal government expenditures (12)--implying an annual figure of $8.4 billion for 2004.

A skeptic might try to justify the neglect of animal life in climate change policy analysis in two ways. First, the value of nonhuman life--and the ESA--is heavily debated, and any particular figure will be easy to question. Second, scientific and conceptual uncertainty about climate and natural systems has clouded any attempt at quantification. In 1996, the Intergovernmental Panel on Climate Change (IPCC) wrote:

Perhaps the category in which losses from climate change could be among the largest, yet where past research has been the most limited, is that of ecosystem impacts. Uncertainties arise both because of the unknown character of ecosystem impacts, and because of the difficulty of assessing these impacts from a socioeconomic point of view and translating them into welfare costs. (13) In this Article, we contend that neither of these reasons can justify the failure to take account of the effects of climate change on animals. First, animal life matters, both for its own sake and because human beings care about it. As noted above, the United States spends billions of dollars to protect a relatively small number of species under the ESA. Contingent valuation studies consistently show high willingness to pay for the protection of animals. Other recent studies have suggested highly significant instrumental value for biodiversity in areas such as agriculture and medical research. Second, the scientific uncertainty over the impact of climate change on natural systems is rapidly diminishing. Many of the most important discoveries have been made only in the past few years, so previous analysts may have been right to assume that scientific knowledge was insufficient to permit precise judgments about damages or causality. But the most extreme claims of causal ambiguity are no longer tenable. While it is an understatement to say that the magnitude of the effects of climate change on animals is still debated, the direction and general significance of those effects are not. Climate change will impose enormous costs on nonhuman life, and ignoring these costs while evaluating climate change policy is no longer excusable.

This Article proceeds in four parts. Part I surveys the recent scientific literature that identifies the potential impact of climate change on animals and other nonhuman life. Part II explores why and how animal welfare might be counted in the evaluation of climate change regulation. Part III offers a partial and highly tentative estimate of the monetized loss from the impact of climate change on nonhuman life. Even under conservative assumptions, focused solely on extinctions and excluding other kinds of animal suffering and death, we estimate that this loss will run into the hundreds of billions annually. Despite the tentativeness of the particular number, the unambivalent conclusion is that the prevailing estimates of the costs of climate change must be dramatically increased.

1. SOME EFFECTS OF CLIMATE CHANGE

   The fact of anthropogenic climate change is no longer in serious dispute. (14) Carbon dioxide levels in the atmosphere have risen to a level probably unseen in millions of years. (15) Global temperatures have increased by 0.6[degrees]C in the twentieth century, and have been projected to increase an additional 1.4[degrees]C to 5.8[degrees]C for the period from 1990 to 2100. Sea levels rose by 0.10 to 0.20 m in the twentieth century, and are expected to rise an additional 0.09 to 0.88 m in the next hundred years. (16) Extreme weather events may begin to occur with increasing frequency.(17) Perhaps most ominously, some scientists have hypothesized that disruptions to the ocean's thermohaline circulation due to warming of polar waters might perversely trigger an abrupt and massive cooling event. (18)

   These climatic shifts are expected to have a series of negative effects on human society. Agriculture will suffer from temperature changes and extreme weather events. Human health will decline, as cases of heat stress increase and diseases such as malaria spread to previously inaccessible regions. Cities such as Venice might be damaged or destroyed by changes in sea level. (10)

   There is significant debate, however, about the proper accounting for these potential harms, especially as they pertain to the United States. William Nordhaus and Joseph Boyer, for example, report that the net cost of gradual climate change to the United States, under moderate scenarios, might be "close to zero" because of adaptive responses. (20) Robert Mendelsohn and James Neumann conclude that climate change will create net benefits in the United States--largely by boosting agricultural production. (21) In contrast, Samuel Fankhauser and Richard Tol both find that climate change will cause more than $60 billion in annual...