efforts are ongoing under the Montreal Protocol and Kyoto Protocol to control rapid growth in the industrial manufacturing and use of these environmentally potent gases. For some applications more benign alternatives such as hydrofluoroolefins have been developed and are being gradually introduced. Climate change feedbacks Current trends in climate change lead to higher ocean temperatures and acidity, thus modifying marine ecosystems. Also, acid rain and polluted runoff from agriculture and industry change the ocean's chemical composition. Such changes can have dramatic effects on highly sensitive ecosystems such as coral reefs, thus limiting the ocean's ability to absorb carbon from the atmosphere on a regional scale and reducing oceanic biodiversity globally. The exchanges of carbon between the atmosphere and other components of the Earth system, collectively known as the carbon cycle, currently constitute important negative (dampening) feedbacks on the effect of anthropogenic carbon emissions on climate change. Carbon sinks in the land and the ocean each currently take up about one-quarter of anthropogenic carbon emissions each year. These feedbacks are expected to weaken in the future, amplifying the effect of anthropogenic carbon emissions on climate change. The degree to which they will weaken, however, is highly uncertain, with Earth system models predicting a wide range of land and ocean carbon uptakes even under identical atmospheric concentration or emission scenarios. Arctic methane emissions indirectly caused by anthropogenic global warming also affect the carbon cycle and contribute to further warming. See also References Further reading (Article about the missing carbon sink.) External links Carbon Cycle Science Program – an interagency partnership. NOAA's Carbon Cycle Greenhouse Gases Group Global Carbon Project – initiative of the Earth System Science Partnership UNEP – The present carbon cycle – Climate Change carbon levels and flows NASA's Orbiting Carbon Observatory CarboSchools, a European website with many resources to study carbon cycle in secondary schools. Carbon and Climate, an educational website with a carbon cycle applet for modeling your own projection. Chemical oceanography Photosynthesis Soil biology Soil chemistry Carbon cycle Numerical climate and weather models Effects of climate change