why are greenhouse gases necessary for life on earth
The natural greenhouse effect has been keeping the earth warm for millions of years, allowing life to thrive on this planet. The enhanced or accelerated greenhouse effect, which is what is happening now, is causing global warming and may mean the end of life on earth if we can't slow or stop it.o this  natural greenhouse effect is very useful.    The gases that keep the earth warm are called greenhouse  gases. The most important gas, causing about 75% of the  natural greenhouse effect, is water vapor.