However, thanks to human intervention, ozone depleting CFCs have been phased out almost completely.
Of the other three problems, global warming is the most serious, and deforestation and air pollution are just some contributors to global warming. Human populations have long been set up around water sources, such as lakes or seas. These towns can quickly develop into big, bustling, overcrowded ports or habours. The problem that this brings is that as the earth warms, glaciers melt faster than they are formed, thus, sea levels rise, and as large populations live by the sea, they have to relocate as their homes get flooded.
Deforestation is happening as humans get more advanced technology and cut down too many trees than the trees can repopulate. There are also other causes, such s illegal logging, wildfires, and the slash-and-burn technique used by farmers to clear land. Trees are a huge carbon basin, as they capture more carbon dioxide (the most abundant greenhouse gas) than any other land plant. When they are burnt, they cannot capture carbon dioxide, and the carbon dioxide that they had captured would be released.
Air pollution is when gases prevent heat from radiating back into space. This heats up the earth, and these gases are called greenhouse gases. The most predominant of these gases is carbon dioxide (cO2). Even though other greenhouse gases trap more heat than cO2, cO2 is still more common. More greenhouse gases is produced when fossil fuels are burnt, which are the remains of ancient plants and animals.
Humans can still save themselves by the easiest ways. Invest in Green Technologies, such as renewable energy, and not waste energy. They can reuse, reduce, and recycle, take public transport, buy legally approved wood furniture, and not use too much plastic (comes from oils and hard to down).