What are the models of the earth’s system and climate?


Earth system models and climate models represent the complex integration of environmental variables used to understand our planet. Models of Earth systems model how chemistry, biology and physical forces work together. These models are similar to global climate models, but much more complete.

To understand the models of the Earth’s system, it helps to first understand the models of the global climate. Climate is a long-term picture of changing weather. It includes temperature, rain and snowfall, humidity, sunlight and wind and how they occur over the years. Climate models explain how these variables can change through mathematical analysis based on the physics of the motion of energy, gases, and liquids combined with measurements made from experiments, laboratories, and other real-world observations.

Models of the Earth system

Models of Earth systems include many interdependent components and processes that help us understand our planet. Credit: Image courtesy of Paul Ulrich, University of California, Davis

Climate models include:

  • An atmosphere that includes clouds, aerosols and gases.
  • The land surface and how it is covered with vegetation, snow and ice, lakes and rivers and soil.
  • Sea ice and oceans.
  • How all of these components store and move the heat and carbon that heat the Earth’s atmosphere.

Global climate models view the Earth as a giant network. The size of each cell in the network is determined by the power of the computer on which the model runs. Just like a video game, a higher resolution requires a much more powerful computer.

Models of the Earth system include all factors in climate models. But no matter how complex the climate, it is only one part of an even more complex system of the Earth. The purpose of Earth systems models is to understand how the Earth functions as a system of interdependent parts. These parts include the physical, chemical and biological processes that interact in the formation of our planet and the organisms on it. The science of the Earth’s system is interdisciplinary, relying on the science of the atmosphere, oceanography, ecology of ecosystems, soil microbiology, multisectoral analysisas well as the major scientific disciplines of mathematics, chemistry and physics.

Models of Earth’s systems can help understand and provide important information about water availability, drought, climatic and temperature extreme features, ice sheets and sea levels, and about land use change. They help scientists understand how plants, humans, animals and microbes contribute to and affect the Earth’s climate. For example, different plants absorb carbon dioxide at different rates. Different landscapes – ice, oceans, natural vegetation, farmland or cities – can change the way the earth absorbs or reflects sunlight. As the temperature and rainfall change the plants respond by changing the carbon balance and atmospheric radiation. In the ocean, the nature of circulation changes the amount of plankton and seaweed.

These factors work on many time scales. The Sahara seems to have gone from wet to dry for thousands and tens of thousands of years. Plants in the wet Sahara absorb sunlight and store carbon, while dry Sahara reflects sunlight and retains little carbon. These factors also operate on a very short time scale, such as the rapid expansion of cities in the 1920sth century into land previously covered with plants, changing the way the earth reflects and stores heat and carbon. Chemical processes from the slow erosion of rocks can emit dust into the atmosphere, trapping more heat in the air. Short chemical processes, such as industrial pollution and soot from forest fires, can have similar effects.

Because Earth system models can include the impact of human decisions, they are useful tools for planning things like infrastructure, energy production and use, and landscape use. For example, a model of the Earth’s system could help plan a coastal city where to build a new highway to ensure that the new highway will not be flooded if hurricanes become more severe in response to global climate change.

Simulation of the entire Earth or the Earth’s climate with sufficient[{” attribute=””>accuracy is challenging for scientists. One solution is to create more powerful computers that can produce high resolution models with sophisticated ways of representing real-world variables. Another is reduced complexity models. These reduced complexity models provide lower resolution climate information but are easier and faster to run. This makes them perfect for research questions that do not require the detailed data provided by Earth system models. Researchers also use simplified models to quickly test narrow hypotheses about the planet. Researchers can also use focused multisector dynamic models to explore the interactions and interdependencies among specific human and natural systems.

Fast Facts

DOE Office of Science: Contributions to Earth Systems and Climate Models

The Department of Energy (DOE) Office of Science Biological and Environmental Research (BER) program supports Earth systems and climate modeling through several related efforts. The Earth and Environmental Systems Modeling program (EESM) develops and applies models to increase scientific understanding of the factors in the integrated Earth system. It works on research as diverse as infrastructure planning and the development of advanced representations of the Earth. To build the computer codes needed to run complex Earth system and climate models on DOE’s fastest computers, DOE supports the Energy Exascale Earth System Model (E3SM) project through the BER Earth System Model Development (ESMD) program. The E3SM is a massive computer model of the planet designed to work on DOE’s Leadership Computing Facility supercomputers. E3SM will provide scientists and policymakers with predictions of the changing Earth system at the spatial resolutions necessary to make informed decisions. Finally, DOE’s Regional and Global Modeling Analysis (RGMA) program advances capabilities to design and analyze global and regional Earth system model simulations. What are the models of the earth’s system and climate?

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