What are the two main sources of threats of the Environment?

What are the two main sources of threats of the Environment?
Simply by existing, people have made major impacts on the world's living ecosystems. This summary attempts to list most of these, so that the enormity of the situation can be observed. A century ago, this list would have been quite short, because human use of the planet's resources was much less, and not perceived as damaging. Today, not only can damage be seen or predicted, it can also be felt personally in the form of shortages and hindrance. Little do we realise, however, to what extent we have changed this planet. In reading this compiled summary, please remember that it reflects just a snapshot of today's situation, and that the world's population is still to double in the coming forty years! Also remember that it lists the doom side of developments, and not the positive actions (like conservation) to alleviate these. So far, such remedies have, at best, been able to postpone the inevitable for a few years. (recycling, fuel efficiency, green engineering, crop genetics, etc.)
Not all changes to the planet's ecosystems are perceived as problems. Only those that affect us are, particularly those that affect us now. All our problems are caused by people, for without people there would be no problems. Thus the more people and the more affluent their lifestyle, the more resources they will use and the more numerous and severe our problems will become. Ecological problems grow faster than the rate of population and the growth of the world economy. For instance, a simple compounded growth of 3% per year will double the world's problems in 25 years; growth of 6% in 12 years! It is not surprising then, that the present generation of school children will experience change as never witnessed before and never to be witnessed again, as humanity exhausts some of its most precious resources, while also causing serious trauma to the environment. The summary below has been divided into four sections, for its effect on humans, the atmosphere, the land, and the sea.
In this summary, we have omitted the benefits of humanity's growth and development, such as major improvements to living standards, security, health, education and the availability and quality of food, comfort, recreation and sport, mobility and so on. These are amply experienced by those who have the fortune to be economically secure. But the downsides of these developments, are often not seen because they happen invisibly, unnoticeably, slowly and somewhere else, and they are not advertised. The tremendous progress made in conservation, is not mentioned here, like the cleaning of rivers, progress in recycling, alternative farming methods and so on. On the other hand, the summary presented here reflects only the tip of the iceberg, being very incomplete.threats to humans: health, food and water, shelter, recreation, hindrance, social cohesion, wealth.threats to atmosphere and water cycle: climate change, sea level rise, atmospheric pollution,threats to land and soil: water, exploitation, soil erosion, species diversity,threats to the sea: exploitation, soil erosion, habitat loss, nutrient discharge