An Ecosystem-Based Approach to Slowing the Synergistic Effects of Invasive Species and Climate Change

Article excerpt

"[I]nvasion is forever. Biological invasions are the least reversible form of pollution." (1)

"[T]he climate change that takes place due to increases in carbon dioxide concentration is largely irreversible for 1,000 years after emissions stop." (2)

INTRODUCTION

Spring is springing earlier these days, an average of ten days earlier than it did just twenty years ago. (3) This scientific phenomenon, called "spring creep," is often ascribed to climate change. (4) Perhaps unsurprisingly, spring creep affects individual species differently. It is a boon to some and a mortal danger to others. However, scientists researching these effects have identified one common theme: spring creep typically favors "invasive species," defined as non-native species that cause environmental or economic harm, or both, (5) and which generally appear to be adaptable to a broader range of climatic conditions. (6) At one site, for example, invasive species now flower eleven days earlier than native species, almost perfectly matching the spring creep. (7) The earlier flowering time confers an advantage on the invasive species, which compete with native species. (8) Warmer temperatures also facilitate the physical movements of invasive species along previously inaccessible pathways (9) and to previously inhospitable environments. (10) Interestingly, it appears that the invasive species return these favors. By upsetting the delicate balance in native ecosystems, invasive species simultaneously increase that ecosystem's susceptibility to climate change-related stressors, and reduce its potential for carbon sequestration. (11)

Even considered separately, invasive species and climate change are each likely to cause significant damage to human health and the environment, as well as enormous economic losses. For example, invasive species place a heavy strain on agricultural systems, they are responsible for a significant percentage of species extinctions, and they are vectors for the spread of disease. (12) Recent studies estimate that invasive species cause worldwide economic damage of about $1.4 trillion yearly, (13) or about 5% of the global economy. For its part, climate change "may well alter the lives of every person on the planet." (14) The economic damages flowing from climate change are less certain, but recent estimates range from 5 to 20% of worldwide gross domestic product. (15)

To consider these phenomena separately, however, ignores the powerful multiplier effect each one exerts on the other. Although a sizable body of research has addressed policy responses to climate change, (16) very little scholarship has addressed the policy response to the invasive species conundrum. And no scholars appear to have addressed the confluence of the two. This article fills that gap, positing that new scientific evidence showing the synergies between climate change and invasive species compels policymakers to consider climate change and invasive species jointly. The synergy between the two will compound the environmental and economic damages each phenomenon causes, and the policy response to each concern should ideally consider the synergistic effects of the other.

Part I of this article examines in detail the synergistic causes and effects of invasive species and climate change, which legal scholarship has entirely ignored to this point. Part II scrutinizes--and finds sorely lacking--federal laws and policies that attempt to control invasive species. One congressionally-commissioned report recently characterized these policies as an "uncoordinated patchwork" that only "partially match[es] the problem at hand." (17) The monumental ecological and economic impacts that invasive species cause are well-known in the scientific literature, but legal scholars have paid little attention to preventing or redressing these harms.

Finally, part III of this article provides early recommendations on the potential scope of and vehicle for a possible solution to the invasive species conundrum, especially in light of climate change. …