Greenhouse effect leads to release of gases like carbon dioxide, nitrogen dioxide and methane in the earth atmosphere. These results in two factors:
1. Global warming: green house gases are hot gases which are increasing the earth atmospheric temperatures. This will result in glacier melting as a result of this many life forms will extinct as they are going to loose their habitat.
2.Air pollution: These gases are chief pollutant of air. If the level of gases exceeds the normal level in air than the air will cause respiratory ailments, or become irrespirable for living organisms.
The sand is just small rocks and pebbles broken down, we know that on a hot day rocks can heat up if left alone for long enough especially if they are dry.