The world is changing, and has already changed. Global temperatures are rising, weather patterns are altering and evidence for these changes being driven by human changes to the composition of the Earth’s atmosphere has (in the view of most mainstream scientists) become compelling.
It is now also becoming clear that the rapid changes to the climate over recent decades have been associated with major changes to the Earth’s ecosystems, species and individual organisms. For example, research at Cardiff School of Biosciences is mapping many of these changes, including case studies as diverse as the impacts of climate change on long-distance migratory birds, disease transmission, interspecific interactions and the structure of ecological communities in rivers, soil and tropical forests. Of course, climate change is not the only ecological issue; the combination of climate change with other human impacts on the environment, such as habitat destruction, pollution and unsustainable harvesting of wildlife (e.g. overfishing) has been described as a “deadly anthropogenic cocktail” which threatens the long-term viability of Earth’s ecosystems.
The film Silent Running is based on the premise that the Earth has already suffered an extreme environmental catastrophe, leading to Earth’s few remaining fragments of forest vegetation being evacuated to a spaceship for safekeeping. This apocalyptic scenario is of course deliberately extreme for cinematic effect, to get us thinking how we would behave in such an unprecedented situation. Yet there is a sense in which we can see Planet Earth itself as a relatively small and vulnerable “spaceship” travelling through the universe, whose fragile and precious ecosystems are the only ones we have left. Indeed, this is one of the great insights obtained by the first astronauts looking down on our home planet from space, seeing Earth for the first time as a tiny yet precious habitable outpost in the vastness of space. The question is; what on Earth can we do to protect it and ensure the survival of its biodiversity, including humanity?
Environmental protection is not straightforward -it is clear that human societies, governments and nation-states consistently fail to act for the good of the planet. Examples of ecologically harmful political and economic structures are innumerable; the Common Fisheries Policy, the Common Agricultural Policy, the abortive Copenhagan climate summit are just a few recent examples, but major human impacts on the environment can be traced back into deep pre-history. These much older examples include the extinctions of native megafauna that coincided with the arrival and spread of humans in Australia and the Americas; the complete deforestation of Polynesian Islands, and the unwitting or deliberate introduction of rats, pigs, goats and rabbits to fragile island ecosystems across the globe.
Case studies of this deadly anthropogenic cocktail of climate change and other human impacts should alarm us; not just because they show us that the biological word is indeed changing rapidly, but because they also highlight how little we currently know about the underlying mechanisms by which climate influences ecosystems, or what we could do to minimise -or even just predict- these ecological impacts. For example, we can describe how ecosystems have responded to climate variability within the historic range, but this does not necessarily let us predict how ecosystems would respond to more substantial climate change in the future. This is because responses of individual species may be non-linear, or community composition and ecosystem function may alter as individual species become extinct. Any or all of these are possibilities, or other, as yet unknown, effects may become apparent; so much is unknown that ecological prediction beyond the recent range of climate conditions remains largely guesswork.
Climate models indicate that even if emissions of greenhouse gases stabilised immediately, the increases in the insulating properties of the atmosphere that have already occurred have committed us to a substantial amount of future warming. Since it is clear that climate change leads to ecological change, substantial ecological changes appear inevitable too. It seems that rather than hoping to prevent climate change, we can only hope to minimise warming as far as reductions in emissions can allow. This means that we need to be pragmatic and focus on how to manage ecological change, for the inherent value of the ecosystems themselves, as well as for the long-term benefit of humanity.
Suggested solutions to the environmental crisis includes “technological fixes” for specific problems, such as “carbon-free” energy from technologies such as nuclear fusion, or by seeding the oceans with iron filings to induce phytoplankton blooms that would act as carbon “sinks”. However, our pragmatism needs to encompass the distinct possibility that humans will accidentally fail to develop workable technologies to achieve these “fixes”, or develop them too late to prevent ecosystem collapse.
This pragmatism also requires a frank appreciation of how human societies, as well as individual humans, behave; our motives as well as our constraints and limitations. For example, we humans are not good at evaluating long-term risk, and we tend to favour our own self-interest, especially over the interests of people we do not know. Similarly, our political structures influence the means by which change is –or is not- possible; governments take a short-term view because they need to be re-elected every 4-5 years, politicians are answerable to their local constituents, or at least to their own nation-state, rather than the global community. Ecologists and conservationists need to acknowledge these human realities (frailties?!) if we are to see meaningful protection of the environment. It is not enough to sigh and wish that humans would be more altruistic –we need to examine the circumstances in which humans have incentives to behave altruistically. The type of incentive may vary; money certainly motivates governments, so our arguments need to be economic as well as moral. Family ties certainly motivate individuals, so our arguments need to encompass our environmental legacy to our own children and grandchildren as well as to the human family as a whole.
The future for Spaceship Earth is uncertain. It does have a future of course, but whether that future includes a healthy environment for humans and for the current diversity of other species, is now largely up to our own generation –in other words, you and me. The responsibility is mind-boggling, and tempting to deny, but there seems no more important issue that the scientific community can address. And despite everything that I have written above, I believe there is room for optimism. Nature is, by very definition, adaptable. And in that sense, nature is resilient. So too is humanity, whose human frailties go hand in hand with traits such as intelligence, morality, and the ability to plan strategically for the future. Climate change may well precipitate the greatest ecological, societal and moral challenges that our species has faced, yet the scientific challenges that lie ahead are exciting, vital and I for one want to be involved!