Melting glaciers

The Planetary Energy Balance [3] of Incoming Solar (340 W/m2) minus Reflected (101 W/m2) minus Radiated (238 W/m2) = 1 W/m2. This excess energy warms the oceans and melts glaciers and ice sheets. The GHG component is 2 W/m2. The amount of heat required to melt enough ice to raise sea level 1 m is about 12 Watt-years (averaged over the planet)—energy that could be accumulated in 12 years if the planet is out of balance by 1 W/m2 per year. 

For example, increased water vapor at high latitudes and the associated increased precipitation, combined with melting glaciers, due to global warming could provide a layer of less dense surface water in the northern Atlantic. Since the conveyor is driven by high-density salt water, this could shut down this global... 

At the end of the last major ice age, about twelve thousand years ago, melting glaciers etched exposed lands with rivers. As climates shifted, new ecosystems appeared and continued to be transformed. Through millennia, either from natural or from man-made causes, jungles evolved into savannas and in many cases became deserts. Coincident with the retreat of the glaciers, the human species became less nomadic and more dependent upon planted crops. Many believe this marked the beginning of the path leading to civilization as we know it today. 

Other wet deposition sources include snow, melting glaciers, and run-off from snowmelt and sea ice. Snow samples collected from a remote location at Palmer Station, Antarctica had an average concentration of 5.6 x 10 M H2O2 (G.W. Miller and D.J. Kieber, unpublished results). Snowmelt run-ofT increased concentrations of H2O2 in surface seawater by more than a factor of two. In contrast, ice melt from sea ice was only slightly higher than surface seawater concentrations (G.W. Miller and D.J. Kieber, unpublished results). 

The Aral Sea s impacts on ecosystems and societies have been positive over time. With regard to ecosystems it has produced a rich environment for a range of flora and fauna, terrestrial and aquatic [7], The region s two major rivers produced two highly productive inland deltas. The stream ecosystems were also abtmdant in species of aquatic life at different stretches of the river. The sea had a steady supply of water each spring from the melting glaciers in the mountains. 

Now that is changing, and fast. You can t open a newspaper without being made aware of the impact of our lives on the planet... the extinction of species, melting glaciers, freak weather events, water shortages and so on, each more... 

Hg from melted ice was measured by reduction to Hg(0), which was purged from solution by bubbling Ar gas. Hg(g) was trapped by metallic Au coated on sand. (Mercury is soluble in gold.) For analysis, the trap was heated to liberate Hg, which passed into a cuvet. The cuvet was irradiated with a mercury lamp, and fluorescence from Hg vapor was observed. The detection limit was 0.04 ng. Blanks prepared by performing all steps with pure water in place of melted glacier had 0.66 0.25 ng Hg/L, which was subtracted from glacier readings. All steps in trace analysis are carried out in a scrupulously clean environment. 

FIGURE 2.4 Melting glaciers illustration. Artwork courtesy of Ms. Vanessa Vaquera of... 

A number of natural hazards result from the interaction and conflict between solid Earth and liquid and solid water. Perhaps the most obvious such hazard consists of floods when too much water falls as precipitation and seeks lower levels through streamflow. Wind can team with water to increase destructive effects, such as beach erosion and destruction of beachfront property resulting from wind-driven seawater. Ice, too, can have some major effects on solid earth. Evidence of such effects from Ice Age times include massive glacial moraines left over from deposition of till from melting glaciers, and landscape features carved by advancing ice sheets. 

When glaeial ice melts, the rock that has been incorporated into it is left behind. This material is called till, or if it has been carried for some distance by water running off the melting glacier it is called outwash. Piles of rock left by melting... 

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