Some Thought One critical environmental issue worthing bearing in mind is the depletion of the ozone layer, which is simultaneously the cause and the consequence of other major environmental problems, such the rise in average global temperature and sea level. Another direct effect of it is the huge amount of solar radiation we are receiving daily, which can lead to cancer among other illnesses. Another environmental problem to consider is the pollution of the rivers which is mainly caused by the industrial sector which produces an enormous amount of toxic waste, which is dumped into the rivers. Not only that but also exhaust fumes emitted to the atmosphere by factories, chimneys, and cars contain an immense amount of hazardous substances that go directly to our lungs and eventually to our bodies. We should not underestimate our own responsibility in this issue either. For example, most of the houses use fireplaces as heating system, fueling them with wet firewood, which produces more foul air that heat, instead of seasoned firewood, even though the thick cloud of smog engulfing the cities.