Themes

The Center concentrates on four major research areas:

• Climate Variability and Change
• Atmospheric Composition and Processes
• Global Carbon Cycle (including terrestrial and marine ecosystems/land use/cover change)
• Global Water Cycle

Research is conducted through in situ and remotely sensed observations, together with component and coupled ocean-atmosphere-land modeling. This multi-pronged approach provides a foundation for understanding and forecasting changes in the global environment and regional implications. Data assimilation and regional downscaling are used to link the observations and models, enabling us to study the interactions between the physical climate system and biogeochemical cycles from global to regional scales.

Climate Variability and Change

Societies around the world expect, and depend upon, a stable, though seasonally variable, climate. Climatic events such as the El Niño/Southern Oscillation (ENSO) disrupt the normal seasonal cycle, heightening awareness that, in reality, climate can vary dramatically from year to year and significantly affect society. Over the past two decades, research has demonstrated that ENSO is an intrinsic oscillation of the coupled ocean-atmosphere system. Other, more sustained, climatic variability’s are known but not well understood, such as the changes in annual rainfall in the African Sahel on decadal and longer time scales; lengthy droughts in the Nordeste region of Brazil; and the 1930s dust bowl in the United States. The rise in atmospheric concentration of greenhouse gases and predictions of global warming and regional climate change are also relevant to studies of climate variability. Taken together, these examples demonstrate the need for better understanding of the coupled climate system, its natural variability, and its susceptibility to human influences, such as increases in radiatively active gases and atmospheric aerosols.

ESSIC’s research is oriented toward understanding, monitoring, and predicting the physical processes responsible for climate variability and predictability on seasonal, interannual, decadal, and centennial time scales. Key components of the research strategy include:

• Focusing on the role of the coupled ocean and atmosphere within the overall climate system (with emphasis on ocean variability) on seasonal to centennial time scales;
• Developing data assimilation methods to merge remotely sensed and in situ observations with models of the climate system;
• Developing and applying regional and global models of the coupled climate system;
• Analyzing remotely sensed, instrumental, and quality-controlled paleoclimatic data sets;
• Studying the response of the climate system to increases in radiatively active gases and aerosols, and to changes in land surface;
• Exploring the predictability of climate variability and climate change, and improving predictions using existing, re-analyzed, and new global observations, enhanced coupled ocean-atmosphere-land-ice-ecosystem models, and paleoclimate records.

Atmospheric Composition and Processes

The atmosphere links the components of the Earth System, including the oceans, geosphere, terrestrial and marine biospheres, and cryosphere. As a result, the atmosphere is the conduit for change on a local, regional and global scale. Natural events and human activities can change atmospheric composition, which in turn alters Earth’s radiative balance. Subsequent responses by the climate system and the stratospheric ozone layer can influence both natural systems and the biosphere. The atmosphere represents the fast response of the coupled Earth System. Given the rapid and often global dispersal of chemical emissions into the atmosphere, the importance of atmospheric observation as an indicator of global change is evident.

ESSIC’s research is oriented toward understanding, monitoring, and predicting the interrelationships of changes in atmospheric composition, climate, ozone-layer depletion, and surface-level chemical and radiative exposure. Key questions involving Earth System interactions include:

• How do atmospheric composition changes alter the radiative balance of the climate system (and vice versa)?
• What are the interactions between the climate system and the ozone layer?
• What are the effects of regional pollution on the global atmosphere, and the effects of global climate and chemical change on regional air quality?
• What effect do human activities and natural ecosystems have on atmospheric composition and, in turn, how are human activities and natural ecosystems affected by changes in atmospheric composition caused by alteration of global and regional climate, ozone- layer/ultraviolet radiation, and pollutant exposures?

Global Carbon Cycle

Recent developments in science, resource management, and public policy have intensified interest in the global carbon cycle. Carbon is important as the basis for the food that sustains human populations, and as the primary energy source that fuels human economies. It also significantly contributes to the planetary greenhouse effect and the potential for climate change. Fossil fuel consumption and land clearing over the past 150 years have caused atmospheric CO2 and CH4 concentrations to increase to a level higher than it has ever been in over 400,000 years. Changes in land management practices and CO2 and nutrient additions can also significantly enhance carbon “sinks.”

ESSIC’s research is oriented toward understanding, monitoring, and predicting the global carbon cycle, including the role and variability of terrestrial and marine ecosystems, land use, and land cover. Key questions involving Earth System interactions include:

• What are the dynamic storages, transfers, and pathways of carbon within the Earth System, and how will this carbon cycling change in the future?
• On longer time scales, what exchanges exist with the lithosphere?
• How do various processes in the ocean and on the land determine the interannual growth rate in atmospheric CO2?
• What are the global patterns of land cover and land use, and how do land management practices affect carbon storage and release?
• What interactions and feedbacks with the physical climate system are induced by changes in terrestrial and marine ecosystems, land use, and land cover?

Global Water Cycle

The behavior of water in the Earth System is central to nearly every aspect of the global climate and crucial to human welfare. Interannual changes in precipitation and evaporation are associated with droughts and floods that threaten the lives and livelihood of millions of people. Evidence indicates that the global hydrological cycle is accelerating, resulting in an increasing number of extreme precipitation events. Improving our understanding of the ways that water influences, and is influenced by, the integrated Earth System is a critical component of our ongoing effort to predict climate variations and anticipate global climate change.

ESSIC’s research is oriented toward understanding, monitoring and predicting the global water cycle, including precipitation, evaporation, storage and transport, on time scales from weeks to centuries. Key questions involving Earth System interactions include:

• What are the dynamic pathways, storages, transfers and transformations of water within the Earth System, and how do they change in association with seasonal to interannual climate variability?
• What are the interactions and feedbacks among terrestrial and marine ecosystems, land use and land cover, and the global water and carbon cycles, and how will these evolve as atmospheric CO2 increases?
• How do regional changes in air pollution affect the local and global behavior of the water cycle?
• What is our ability to reproduce/assimilate, simulate and/or predict the water cycle and/or its components at global and regional scales using the state-of-the-art models and data assimilation systems?
• What new observations are needed to improve our understanding of the water cycle?
• How will the humidity of the stratosphere and upper troposphere change in response to anthropogenic CO2 emissions, and how will these changes influence other aspects of global change?
• How will global climate change and human activities on land affect the ocean-continental margins, biogeochemistry, ecosystems, and fisheries?
• What are the connections between land-ocean interactions and human health, and how will they be influenced by global climate change?