Climate Change and Biogeochemical Impacts

• Main Authors: Doney, Scott C, Schimel, David
• Format: Other/Unknown Material
• Language: English
• Published: Wiley 2015
• Subjects: Ocean acidification
• Online Access: http://dx.doi.org/10.1002/9780470015902.a0003242.pub3; https://onlinelibrary.wiley.com/doi/pdf/10.1002/9780470015902.a0003242.pub3; https://onlinelibrary.wiley.com/doi/full-xml/10.1002/9780470015902.a0003242.pub3

Abstract Human activities are causing a significant build‐up of heat‐trapping greenhouse gases (e.g. carbon dioxide, methane and nitrous oxide) and aerosols in the atmosphere driven by emissions from fossil fuel combustion, industry, agriculture and deforestation. Atmospheric carbon dioxide is more than 40% above preindustrial levels and growing, and levels would be even higher without modulation by land biosphere and ocean uptake. Model projections for the coming century suggest that these changes in atmospheric composition will result in substantial global warming and strengthening of the hydrological cycle and there is growing observational evidence of a substantial alteration in climate patterns. Carbon cycle ( CO 2 and CH 4 ) feedbacks to climate from the land and ocean can significantly affect future climate, but current projections of these effects are highly uncertain. Climate change and other human‐driven processes such as land‐use changes and ocean acidification will have profound impacts on global biogeochemistry and terrestrial and marine ecosystems. Key Concepts The carbon cycle will have a significant impact on the amount and pace of future climate change. Atmospheric levels of CO 2 , other greenhouse gases (CH 4 and N 2 O) and some aerosols have increased substantially above preindustrial levels due to human activities. Changing atmospheric composition alters the radiative balance of the planet and the resulting climate impacts reflect many feedback mechanisms that can either amplify or diminish the initial perturbation. Global‐scale climate warming, changes in the water cycle and melting of the cryosphere are already underway, and these trends are projected to continue into the future. Fossil‐fuel use transfers carbon from a long‐lived geological reservoir to the atmosphere–land–ocean system where excess CO 2 can reside in the atmosphere for many centuries. The biosphere and oceans mitigate some of the effects of fossil fuel burning and deforestation but the future of these carbon sinks under an ...