Geography 2152F/G Lecture 6: Geo of Hazards - Lecture 6

• School: Western University
• Department: Geography
• Course: Geography 2152F/G
• Professor: Mark Moscicki

Document Summary

Through earth(cid:859)s e(cid:374)tire histor(cid:455) (cid:894)(cid:1008). (cid:1010) (cid:271)illio(cid:374) (cid:455)ears(cid:895), the (cid:272)li(cid:373)ate has al(cid:449)a(cid:455)s (cid:271)ee(cid:374) (cid:272)ha(cid:374)gi(cid:374)g. Over the last billion years, there have been several worldwide ice ages. Between ice ages, the global climate was at times slightly warmer than it is today. *the concern is not the actual temperature; it is the rate of temperature change. All of canada was covered with ice 18,000 years ago (except for norther yukon. ) Lower sea levels at that time exposed the bering land bridge. There has been a rapid rise in temperature over the past 100 years. This corresponds to human industry and the increase of greenhouse gases. There are four general causes: variations in solar radiation, changes in composition of the atmosphere, cha(cid:374)ges i(cid:374) earth(cid:859)s surfa(cid:272)e, variatio(cid:374)s i(cid:374) the earth(cid:859)s or(cid:271)it. The sun tends to emit more energy during periods of high sunspot activity. Solar output regularly changes on the order of 0. 1 0. 2% in relation to sunspot cycles.