November 18, 2009
Research Challenges For Understanding Landscape Changes Identified
Nine research challenges and four research initiatives that are poised to advance the study of how Earth's landscapes change were unveiled today in a new report by the National Research Council. These challenges and initiatives could open the path to resolving environmental issues, from coastal erosion to landslides, by helping predict how processes such as wind, ice, water, tectonics, and living organisms drive changes in the Earth's surface.
The development of new analytic and computing technologies and the heightened demand for scientific guidance in decision making concerning future landscape transformation and restoration have propelled research in Earth surface processes over the past two decades. However, significant questions remain unanswered, which are addressed in these challenges and initiatives.
WHAT DOES OUR PLANET'S PAST TELL US ABOUT ITS FUTURE? The surface of the Earth records its own evolution, which scientists can examine through evidence in ice cores, sediments, and landforms. Accelerating the ability for researchers to tap into that record could help determine how the surface environment alters through time and how it may change in the future.
HOW DO GEOPATTERNS ON EARTH'S SURFACE ARISE AND WHAT DO THEY TELL US ABOUT PROCESSES? From repeated patterns on sand dunes to similar shapes of barrier islands, myriad land patterns at all scales can be seen on the planet's surface. Scientists have found that these geopatterns often emerge spontaneously, evolve over time, and are resilient, as unstable patterns do not last for long periods. Geopatterns provide a template for understanding many Earth surface processes, which could help scientists predict how the surface will respond to natural and human-induced changes.
HOW DO LANDSCAPES INFLUENCE AND RECORD CLIMATE AND THE MOVEMENT OF LARGE PIECES OF THE EARTH'S CRUST? One of the advances in the earth sciences is the recognition of interactions between climate and the movement of Earth's tectonic plates. For example, in mountain ranges developed from converging tectonic plates, prevailing winds may force clouds, rain, and glaciers to remain on one side of the range, which could increase erosion. Such concentrated erosion draws more rock upward from within the Earth, increasing the height of the range and further affecting local climate patterns. Scientists are searching to quantify the interactions and feedbacks among landscapes, tectonics, climate, and life. For instance, how much could climate change increase rainfall, which in turn would increase the frequency of erosion from landslides?
HOW DOES THE BIOGEOCHEMICAL REACTOR OF THE EARTH'S SURFACE RESPOND TO AND SHAPE LANDSCAPES ON LOCAL TO GLOBAL SCALES? The chemical erosion and weathering of bedrock and soil are among the least understood of the geological processes. They are often major factors in how landscapes change because of their effects on climate, groundwater and river chemistry, strength of rocks, erosion, and availability of nutrients in soils. Gaining insight into the nutrient cycle essential to both living organisms and climate, for example, will allow scientists to address the effects of human-induced changes to land and groundwater.
WHAT ARE THE TRANSPORT LAWS THAT GOVERN THE EVOLUTION OF THE EARTH'S SURFACE? Quantitative approaches are needed to define how and at what rates a process like erosion can shape the landscape. Significant progress has been made in developing and applying mathematical formulas known as "transport laws" to gauge the rate at which soil is transferred or a river can cut through bedrock. Nonetheless, scientists still need to establish the transport laws for processes such as landsliding, transport and deposit of mud, and glacial and chemical erosion.
HOW DO ECOSYSTEMS AND LANDSCAPES CO-EVOLVE? Living organisms strongly influence the form and pace of surface erosion, and they control the nutrient cycle with simultaneous effects on climate, hydrology, erosion, and topography. Coordinated efforts to identify connections among life forms, surface processes, and landscapes are under way at various field observatories. However, greater knowledge is needed to develop predictive models and perform experiments that explore the causes, effects, rates, and magnitudes of life-landscape interactions.
WHAT CONTROLS LANDSCAPE RESILIENCE TO CHANGE? Some areas of Earth's surface are more vulnerable than others to change. For example, polar and glacial regions are nearing or are in a state of flux predicted to continue with global warming. Scientists need to better understand how rapid and abrupt changes occur and the factors and processes that make landscapes resilient to these changes.
HOW WILL EARTH'S SURFACE EVOLVE IN THE NEW ERA? The term "Anthropocene" has been suggested to describe a new era in which humans have become dominant. Understanding, predicting, and adjusting to changing landscapes increasingly altered by humans constitute pressing challenges, and science is far from developing a general theory of coupled human-natural systems.
HOW CAN SCIENCE CONTRIBUTE TO A SUSTAINABLE EARTH SURFACE? With increasing scientific knowledge of the causes and long-term effects of human-induced changes to land, a consensus has emerged that at least some of these disrupted landscapes can and should be restored or redesigned. Researchers, practitioners, policymakers, and the public have recently begun to examine the success and limitations of past restoration efforts. Earth surface scientists can contribute to these efforts and provide guidance in future decisions regarding natural and managed landscapes.
In addition, the report proposes four research initiatives, derived from the nine challenges, to provide promising pathways for scientific guidance on issues related to planning, mitigation, and response to changes in the Earth's surface now and in the future. The four research areas would delve into understanding interacting landscapes and climate, the co-evolution of ecosystems and landscapes, quantitative reconstruction of landscape dynamics across time scales, and the future of landscapes in the Anthropocene.
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