Climate Change in the Arctic - The Changing Arctic Environment: The Arctic Messenger - page 235

and, ultimately, rocks. In the course of geological time, these rocks will be thrust above the
sea.Subsequenterosionleadstothecarbonfindingitswaybackintotheatmosphere by,for
example, biological uptake followed by respiration. Under certain conditions of heat and
pressure, sediments containing large accumulations of organic matter give rise to carbon-
rich products that are collectively called fossil fuels , such as oil, gas and coal. When we
burn them, we are short-circuiting the carbon cycle.
The reservoirs vary in their capacity to hold CO 2 . Most CO 2 is contained in the litho-
sphere. The transfer rate (flux) between reservoirs also differs. For example, fluxes into
and out of the lithosphere normally run at a snail's pace. Prior to the onset of the Industrial
Revolution (about 1750), the dynamics of this system had settled for a very long time into
a status quo, where the atmospheric concentration of CO 2 was held at about 280 parts per
million (ppm). It was this concentration that maintained our historical average global sur-
face temperature of about +14°C.
The situation that has evolved since the 1750s is that the engine of the Industrial Re-
volution and of our present-day world economy runs on fossil fuels. Inadvertently, we have
found a way to rapidly move massive quantities of carbon stored in the lithospheric reser-
voir into the atmosphere. We do it every time we burn fossil fuels. Our ability to release
CO 2 into the atmosphere is much greater than the ability of natural mechanisms to remove
CO 2 into another reservoir, mainly the oceans and, ultimately, sediments. By analogy, be-
fore 1750, the tap and the drain of my bathtub were set at the same flow rate, but now the
tap is flowing faster than the drain. Infact, between 1750(the start ofthe industrial era) and
2011, humankind has injected about 375 billion tonnes of carbon as CO 2 emissions into the
atmosphere. When the Kyoto Protocol to the United Nations Framework Convention on
Climate Change (UNFCCC) was adopted in 1997, the annual average CO 2 concentration
measured at the observatory on Mauna Loa in Hawaii stood at 363.76 ppm. By 2012, it
stood at 393.84, and in 2013, it had reached 396.48 while intermittently overshooting 400
ppm. The consequence of this increasing accumulation of anthropogenically derived CO 2
in the atmosphere is that the average global temperature is moving upwards as dictated by