Abrupt Change in Earth's Climate System

Abstract

Many aspects of Earth's climate system have changed abruptly in the past and are likely to change abruptly in the future. Although abrupt shifts in temperature are most dramatic in glacial climates, abrupt changes, resulting in an altered probability of drought, large floods, tropical storm landfall, and monsoon rainfall, are all important concerns even in the absence of significant anthropogenic climate forcing. Continued climate change will likely increase the probability of these types of abrupt change and also make abrupt changes in ocean circulation and sea level more likely. Although global warming may have already triggered abrupt change, current understanding and modeling capability is not sufficient to specify details of future abrupt climate change. Improved adaptation strategies are warranted, as well as efforts to avoid crossing climate change thresholds beyond which large abrupt changes in sea level, ocean circulation, and methane-clathrate release could greatly amplify the impacts of climate change.

Cultivation of methanogenic community from subseafloor sediments using a continuous-flow bioreactor

“…A large quantity of methane is stored in the subseafloor as free gas, dissolved methane in the pore water or as hydrates and comprises approximately 500-2500 Gt of methane carbon (Milkov, 2004). Subseafloor methane has also attracted attention as an energy resource, but methane is also a powerful greenhouse gas that is critical in the history of Earth's carbon cycle and climate changes (Schoell, 1988;Kvenvolden, 1995;Overpeck and Cole, 2006). Because isotopically light methane (that is, 13 Cdepleted methane carbon) is globally distributed in subseafloor sediments, subseafloor methane may be largely mediated by microbial activities that cause enzymatic fractionation of carbon species (Milkov, 2004).…”

Tropical agriculture and global warming: impacts and mitigation options

“…The quantification of GHG contributions due to fossil fuel burning is more exact, since the quantities of petroleum, charcoal and natural gas extracted and consumed per year in the world are well known (Overpeck & Cole, 2006). The contribution of agriculture and land use changes are more difficult to be estimated, since the sources are diffuse and the systems more complex (Gregory et al, 2005).…”

“…Firstly, it exacerbates global climate change, which has a negative feedback in the global food production (Knorr et al, 2005). Food production can suffer from climate change impacts such as alteration in solar radiation period and extreme weather events (IPCC, 2001;Overpeck & Cole, 2006). Secondly, the illegal and random deforestation reduces crop production by jeopardizing environmental services such as crop pollination, genetic resources, clean air and water supplies (Foley et al, 2005), soil fertility and erosion (Bertol et al, 2005), pests and pathogen controls that help to maintain crop production (Ghini & Morandi, 2006).…”

Testing the influence of climate, human impact and fire on the Holocene population expansion of Fagus sylvatica in the southern Prealps (Italy)

“…It seems likely that future distributions of species ranges will change in response to current climatic changes (Intergovernmental Panel on Climate Change (IPCC), 2001; Thuiller et al, 2005;Overpeck and Cole, 2006), but predicting the rate and direction of species ranges is complex, because environmental interactions and disturbance may influence biotic responses to climatic change (Overpeck and Cole, 2006). Therefore understanding what has been driving changes in population abundances and species ranges in the past may lead to better predictions of future biotic responses to climatic change (Peteet, 2000).…”