What are advantages and disadvantages of global actions

Explanation: advantages :

1-The Arctic, Antarctic, Siberia, and other frozen regions of the earth might experience more plant growth and milder climates.

2-The next ice age could possibly be prevented.

3-The Northwest Passage through the formerly icy Canadian Arctic Archipelago could arguably open up to transportation.

4-Fewer deaths or injuries would occur due to arctic conditions.

5-Longer growing seasons could mean increased agricultural production in some areas.

6-Previously untapped oil and gas reserves might become available.

disadvantages: Changes in ocean circulation and the resulting warmer temperatures disrupt the world's normal weather patterns, bringing about more extreme weather and an increased frequency of severe and catastrophic storms, such as hurricanes and typhoons. The increase in severe storms leads to a more frequent occurrence of such things as "hundred-year floods," decimation of habitats and property, not to mention, loss of life—human and otherwise.  

Higher sea levels lead to flooding of lowlands. Islands and coastlines are engulfed by water leading to death and disease due to flooding.

The acidification of warming oceans leads to a loss of coral reefs. Coral reefs protect shorelines from heavy waves, storms, and floods and while they only cover about 0.1% of the ocean floor, reefs provide a habitat for 25% of the ocean's species.2  Demolished reefs lead to increased erosion and coastal property damage and the extinction of species.

Warming ocean waters means increased melting of glaciers and ice sheets. Smaller ice sheets form each subsequent winter, which has a devastating impact on the habitat of cold-climate animals and the Earth's reserves of freshwater. (According to the United States Geography Survey [USGS], 69% of the Earth's ice is locked in ice and glaciers.)3

tunami b/c it is near water