Page 363 - Geosystems An Introduction to Physical Geography 4th Canadian Edition

Chapter 11 Climate Change 327
(a) Athabasca Glacier in Canada’s Rocky Mountains, 1917.
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(b) Athabasca Glacier, 2005. The glacier margin has retreated more than 1.5 km in the past 125 years.
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(c) Data from glaciers worldwide show negative mass balance every year since 1990 (indicated by gray bars). The red line shows the cumulative annual balance.
▲Figure 11.19 athabasca glacier and annual glacial mass balance (the gain of snow minus the melt losses) show net losses of glacial ice. glaciers grow when annual winter snowfall exceeds annual summer melt losses; when snowfall and melting are equal, glacial mass balance is zero (see discussion in Chapter 17). [(a) nOaC/ZUMa Press/newscom. (b) gary Braasch/World View of global Warming. nOaa graph adapted from State of the Climate in 2012, Bulletin of the american Meteorological Society report.]
Georeport 11.1 Rainfall over Australia Temporarily Halts Global Sea-Level Rise
The discovery of complicated interactions and unexpected system responses within earth’s climate system is common in cli- mate change science. For example, for an 18-month period beginning in 2010, global mean sea level dropped by about 7 mm, offsetting the consistent annual rise in recent decades. new research shows that heavy rainfall caused vast amounts of water to collect on
the australian continent during 2010 and 2011, temporarily slowing global sea-level rise. The unique topography and soils of the australian continent enable water to collect on the continental interior, where it eventually evaporates or infiltrates into the soil rather than running off to the ocean. The heavy rainfall over australia was generated by the unusual convergence of distinct atmospheric patterns over the indian and Pacific Oceans. Since that time, rain over the tropical oceans has returned to the normal, heavy patterns, and sea level is rising once again.
Yearly ice gain or loss (mm water)
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Cumulative ice loss (mm water)