The Earth’s variable and changing climate system: past to present to future

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Venkatachalam Ramaswamy

NOAA-GFDL, Princeton University, USA

: Expert Opin Environ Biol

Abstract

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The Earth’s climate system comprises the components of atmosphere, oceans, land, and ice. The processes occurring in the system, and the interactions across the components, yields the climate as we know it. Climate comprises an array of variables, with the most commonly known and experienced being temperature at all heights in the atmosphere and depths in the ocean, and precipitation including vapor, liquid and solid forms. These are linked to factors such as atmospheric composition in the form of gases, aerosols and clouds, winds at different altitudes in the atmosphere, salinity in the oceans, land-surface vegetation and soil features, ice on the surface of the land and oceans, and marine and terrestrial ecosystems. Observations from different platforms, together with mathematical modeling governed by laws of physics and chemistry, form the basis of a robust understanding of the Earth’s climate system. In the industrial era (since 1860), human influences such as emissions of well-mixed greenhouse gases and aerosols have affected the planet’s climate, competing with or even dominating over periods the natural “drivers” of climate change such as solar irradiance changes, volcanic eruptions, and internal variability. Observations over the 20th century reveal that several climate variables of direct interest to society have undergone substantial changes e.g., temperature, rainfall, sea-level. Using the NOAA/GFDL state-of-the-art global climate model, numerical simulations of climate change are conducted. These results enable us to analyze the mechanisms that have forced changes in climate. The degree to which the observed phenomena and changes in temperature and rainfall over the different continents can be explained constitutes an advance of the frontiers of knowledge. The detection and attribution of climate changes over the past century establish the foundation for making credible projections of climate e.g., forecasting the extremes and/or shifts in climate over the 21^st century including characterization of uncertainties.

Biography

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Venkatachalam Ramaswamy is Director of NOAA’s Geophysical Fluid Dynamics Laboratory (GFDL), and Professor in the Atmospheric and Oceanic Sciences Program at Princeton University. His research interests are the mathematical modeling of the global climate system and advancing the understanding of the physics and chemistry of the atmosphere. He directs one of the world’s premier climate researches and modeling centers, developing advanced numerical models for understanding and predicting weather and climate. Ram has been a Lead Author on the world’s major scientific assessments, and was a Member of the Intergovernmental Panel on Climate Change team that was a co-recipient of the 2007 Nobel Peace Prize.

E-mail: ramaswamy149@gmail.com