An Earthwatch Roundtable
Can ecosystem research help us prepare for future climate change?
The impacts of global warming will have enormous consequences for the Earth's ecosystems, yet these impacts are still only poorly understood.
We asked four Earthwatch-supported scientists how their research can help us not only predict the impacts of climate change, but help mitigate those impacts and adapt ecosystems to new climate regimes.
Centre for Tropical Biodiversity & Climate Change, James Cook University
Principal investigator of Earthwatch's Climate Change in the Rainforest project
Australia's Wet Tropics
The ecological impacts of global climate change will depend on two factors: the final degree of change and the resilience of the ecosystem in question. The first factor can only be addressed globally and at a governmental level by reducing global greenhouse gas emissions. However, the second issue, of resilience, can be addressed locally.
Global warming can have a particularly strong impact on mountainous regions like Australia's Wet Tropics World Heritage area, where the mountaintops exist as cool islands in a sea of warmer climates. These islands provide habitat for organisms unable to survive and reproduce in warmer climates. Almost all plants and animals unique to this region are adapted to these cooler uplands. Climate change will likely result in species ranges shifting up mountains, however many animals are already restricted to the mountaintops. There is no room for latitudinal movement either, as there is no rainforest for hundreds of kilometers to the north or south.
Successful long-term conservation of the Wet Tropics will require a number of management actions that cannot be implemented without further research. For example, it is possible that suitable habitat for many Wet Tropic species will only occur thousands of kilometers to the south in 100 years time. Managers need to know where this habitat might occur and consider the implications of such changes. Research may also identify regions within the Wet Tropics that can act as greenhouse refugia, where threatened plants and animals can survive despite warming, making it imperative to protect and manage these areas now.
The Canadian Arctic
We need to find out more about the natural capacity of species to adapt to the changing climate, so that we can direct our conservation efforts toward the most vulnerable species and not waste valuable management resources on species that can cope naturally. Only thorough field research can advise these decisions. Until then, we need to maintain the health of our natural ecosystems in order to maximize their natural resilience and minimize the impacts of climate change.
Humans tend to focus on the potential economic effects of climate change rather than the ecological ones. Our species has the ability to quickly respond to changes in our environment, a characteristic not shared by most of the rest of the Earth's organisms. These species live and function as part of natural ecosystems that, over thousands to millions of years, have developed ecological interactions that are complex, dynamic, and subtle.
Experiments have been designed to assess the ecological effects of warming, but these are often focused on simple cause-effect relationships among a few ecosystem components that have been isolated for study. Our ability to manipulate and measure ecosystem processes is limited, generally oversimplifying the complexity of natural systems, but arguably improving. In this fashion we are slowly improving our understanding of the way ecosystems function in the face of climate change.
For example, there is more appreciation for the soil and the role of nutrients in stimulating the "producers" that ecosystems are built upon. A warming atmosphere at high latitudes and elevations has warmed soils, which promotes nutrient cycling and increases nutrient pools available to plants. Increases in carbon dioxide and methane emissions from decomposition are a byproduct. In the Arctic where I work, global warming appears to accelerate permafrost thawing, leading to the decomposition of ancient, stored carbon in northern peatlands. This could further enrich atmospheric greenhouse gasses and amplify global warming. As we improve our understanding of these subtle interactions we improve our ability of predict consequences of climate change, but there is much work needed to advance our knowledge.
The simplest way to mitigate these changes is to reduce emissions from sources that our species largely controls - e.g., hydrocarbon combustion and forest clearance. The world's natural areas must cope with the ecological changes driven by global warming but also with the increasing pressures exerted by increasing human demands for space and resources. Change is part of our world but the pace at which it is occurring today is unparallelled in human history.
Dr. Lee Dyer
Principal investigator of Earthwatch's Forest Caterpillars project.
Here in New Orleans, we are on the front line in the war with climate change. The hurricanes, floods, and droughts in Louisiana over the last year are the exact scenario predicted by climate change models for decades. It is irrelevant whether or not such specific weather events are due to human activities. The relevant fact is that we need to be prepared for these events, because they will increase in frequency and intensity. Another major city will be destroyed by an extreme weather event in the near future, and more ecosystems will be devastated. Are we ready to adapt, mitigate, or even understand what these events mean to urban, managed, and natural ecosystems? Not yet.
As climate change research continues to intensify, we will certainly be better positioned to deal with the myriad of complex changes in biotic systems. Our research shows that extreme weather events such as floods and droughts can cause increases in caterpillar outbreaks via disruption of parasitism by wasps. Caterpillars are among the most important leaf-eaters in forests and in agricultural systems, with billions of dollars spent annually trying to control them. Our research has demonstrated that the best strategy for controlling caterpillars is to enhance the natural conditions that keep their populations in check. Thus, an important plan for adaptation and mitigation of climate-induced insect outbreaks is to enhance populations of "parasitoids" - the parasitic wasps and flies that are the most important source of mortality for most caterpillars.
Next summer I expect to see outbreaks of several species of caterpillars in New Orleans. What should we do about it? Nothing yet. Fortunately, although climate change is a real part of life here, the "biblical plagues of insects" that some reporters have asked us about are still science fiction. However, I am sure that persistent declines in parasitoids over the coming decades will bring outbreaks that exceed the imaginations of most authors. It is more than a good idea to carefully examine existing parasitoid communities in any ecosystem and to learn how to keep their populations thriving.
The Open Ocean
Dr. Rob Thomas
Principal investigator of Earthwatch's Storm Petrels over Portugal project.
The Portuguese have a long and proud association with the ocean. The fish landed by Portugal's trawler fleets provide an important part of the national diet. Climate change predictions for mainland Portugal forecast substantial temperature increases of 3-4.5ºC over the next 80 years, and climate change will almost certainly continue to affect the ocean's temperature, the path of the Gulf Stream, and hence the ecosystems which both commercial fisheries and seabirds depend on for their survival. Our research focuses on what seabirds can tell us about the ecological impacts of climate change in Portuguese waters and beyond, taking the long-distance migration behavior of the European storm petrel as the main case-study.
Migrant birds must build up large energy reserves, mainly as fat, to fuel their migration journeys. Their ability to do this, and the level of fat reserves carried, depends on conditions along the migration route. Our project reveals that the fat reserves of migrating petrels are a sensitive indicator of climate-linked biological changes in the north Atlantic. Storm petrels therefore appear to be useful "sentinels" of climate change, providing early-warnings of climate-driven changes in marine ecosystems.
However, a key message from this project is that we actually know very little about even the basic details of the lives of these mysterious seabirds and the ecosystems on which they depend. For example, a major problem in understanding the impacts of changing sea temperatures on storm petrel migration strategies is that we currently know very little about what the birds are eating during migration, and how these food species are in turn being affected by sea temperatures. It is through the hard work of Earthwatch volunteers that we are beginning to fit together the pieces of this ecological jigsaw puzzle.
By providing hard facts and thorough case studies that illustrate the biological effects of climate change, our hope is that environmental policy makers will be better able to draw informed, accurate conclusions and to develop appropriate responses to promote the survival of marine biodiversity in the face of climate change.