First, absorption helps people by preventing high-energy radiation from reaching the surface which limits our exposure to harmful radiation. The atmosphere absorbs most of the radiation from the ultraviolet region through the X-ray region. The second way in which absorption helps the earth is as a heat source for it.
*lean times (ahead). Fig. a future period of lowered income or revenue; a future period when there will be shortages of goods and suffering. (*Typically: be ~; cause ~; have ~; mean ~ .) The economy is going sour which means lean times ahead.
Leanness, on the other hand, refers to the muscle, bone, and fat composition of your body weight. Although some lean individuals may actually weigh more than their tabled ideal body weight, low body fat lessens the risk of health problems.