36) What is the largest potential global impact associated with the melting of the frozen peat in northern Canada and Siberia? A) The melting of the peat will release a large amount of carbon dioxide into the atmosphere. B) The melting of the peat will cause for a positive feedback loop as the release of methane will cause an increase in temperature and, consequently, more melting. C) It will cause an increase in fossil fuel use as people would need to move away from the area. D) The change in temperature will cause for an increase in water content in the subsurface leading to the lubrication of faults and ultimately increased earthquake activity. E) The melting of the peat will release a large amount of water vapour into the atmosphere. 37) Which of the following processes is major part of the greenhouse effect? A) ozone trapping incoming ultraviolet radiation from the Sun B) carbon dioxide trapping incoming ultraviolet radiation from the Sun C) water vapour trapping incoming ultraviolet radiation from the Sun D) ozone trapping outgoing infrared radiation from the Earth E) water vapour trapping outgoing infrared radiation from the Earth 38) For records prior to the 1950s, where do scientists obtain evidence showing atmospheric concentrations of carbon dioxide? A) from air samples collected from the top of Mauna Loa in Hawaii B) from air bubbles trapped in ice in Greenland and Antarctica C) from written historical records of human fossil fuel burning D) from the chemistry of deep sea sediments E) from gases dissolved in the ocean 39) Which of the following greenhouse gases makes the largest contribution to the anthropogenic greenhouse effect? A) carbon dioxide B) methane C) nitrous oxide D) ozone E) CFC-11 40) How did scientists estimate variations in solar output in the past, before direct measurements? A) by measuring carbon-14 concentrations in tree rings B) by measuring carbon dioxide concentrations in ice cores C) by measuring ozone concentrations in ice cores D) by measuring the changing extent of Arctic sea ice E) by measuring changes in distribution of terrestrial plants Â