The Science of LCLUC

Key Science Questions

The LCLUC research program focuses on these components in addressing the following key land-use science questions:

  • Where are land-cover and land-use changing, what is the extent and over what time scale and how do the changes vary from year to year? (Variability)
  • What changes are occurring in global land-cover and land-use, and what are their causes? (Forcing)
  • What are the impacts of climate variability and changes on LCLUC and what is the potential feedback? (Responses)
  • What are the consequences of changing land-use activities for ecosystems and how do they respond to and affect global environmental change? (Consequences and Responses)
  • What are the consequences of land-cover and land-use change for human societies and the sustainability of ecosystems? (Consequences)
  • How will land-cover change on time scales from years to centuries? (Prediction)
  • What are the projected changes in land-cover and their potential impacts? (Prediction)

LCLUC Science Components

The focus of LCLUC research is on quantifying the location, extent and variability of change, the causes or forcing factors of change, for example, climatic, ecological and socioeconomic drivers, the processes of change and the responses and consequences of change. NASA LCLUC research projects use a combination of space observations, in situ measurements, process studies and numerical modeling. As an interdisciplinary research program, LCLUC fosters strong partnerships between physical and social scientists to develop the integrated science necessary to understand why and how patterns of land-use and land-cover are changing, how they will change in the future and the implications of these changes. LCLUC research crosscuts several other research areas, e.g. climate change and variability, water cycle, carbon cycle, ecosystems and biodiversity, and human contributions and responses to environmental change.

Variability: The current spatial pattern of land-cover is a result of previous and current land-use. Quantifying the location, extent and trends of recent land-cover and land-use change is an important component of land-change science. Satellite systems often provide the only means to inventory land-cover and monitor land-cover change in a timely fashion. NASA has developed procedures for wall-to-wall mapping of land-cover and spatially explicit monitoring of land-cover change. Systematic long-term observations of land-cover are essential to enable scientists to quantify the rates of change and their variability over time. Establishing consistent long-term data records of land-cover is an important objective for the LCLUC Program.

Forcing: To make a projection of how land-cover will change in the future and to be able to better manage land-use it is important to understand the drivers of change. These include the local and proximate physical, socioeconomic and demographic causes of change, as well as the broader global and regional climatic or macroeconomic forces of change. Quantifying processes of land-use change is undertaken by combining in-situ measurements and ground surveys with satellite data. This is often done through regional case studies.

Responses and Impacts: The impacts of land-use change can be biophysical and socioeconomic and they can be positive and negative. Changes in forest cover can affect carbon sources and sinks, local water resources and biodiversity through landscape fragmentation. Changes in fire regimes can affect ecosystem structure, trace gasses, aerosol emissions and water quality. Overuse of marginal lands leads to degradation and impoverishment affecting human livelihood. Agricultural intensification through the use of fertilizers can improve crop production but may degrade water quality. Changes in land-use can affect human health by changing insect habitat or disease vectors. Agricultural abandonment leads to changes in land-cover, for example, by increasing woody vegetation. Urban expansion and suburban development can result in a loss of agricultural lands or wetlands. Changes in land-use can affect local and regional climate.

Prediction and Feedbacks: Modeling of land-use change provides a means to understand the consequences of different land management options and study the feedbacks. For example, coupled land-use and dynamic vegetation models are needed to understand the impacts of future land management on carbon budgets. Recent trends in land-use change and an understanding of the processes of change provide a point of departure for predictive modeling. Spatially explicit modeling of land-use is needed to study scenarios of land change under different land-uses for a large number of science applications. There are a number of approaches for modeling land-use that are currently being investigated, including statistical empirical models, cellular automata and agent-based modeling. Better understanding the impacts of land-use change on climate and the impacts of climate change on land-use is also needed.

Underpinning the Earth science research paradigm (variability-forcing-response-consequences-prediction) is an ongoing program of LCLUC research, which includes the development of new algorithms, methods and techniques for characterizing, monitoring and modeling land-cover and land-use change and validating derived products. This is achieved by combining the new methods and land-use models with remote sensing and GIS. Development of techniques for data management and analyses are needed to handle the large volumes of data needed for global and regional monitoring and analysis. Global and regional data sets of land-cover characteristics developed within this program support the NASA modeling activities and provide the long-term data records needed to study trends.