Humans can affect the environment in many ways, including air, water, land, noise pollution, soil erosion, global warming, oil spills etc.

Each of these factors affect the environment. For example, oil spills cut off supply of air to the underwater organisms thus causing problems in the environment.
Soil erosion causes reduced fertility of soil, meaning that trees/plants don't grow well. Global warming causes ice caps to melt, therefore, a rise in the water level of the oceans, impacting the environment of the world.

All these factors are caused by humans. Human ships and tankers spill oil in the emission. Increased emissions of greenhouse gases from factories and industries causes global warming. Soil erosion is caused by deforestation, i.e. cutting of trees to clear land. Even animals are killed for meat, hide, claw, skin or even simply for sport.

Thus, we can see that human activities greatly impact the environment in a negative way.

Hope I helped. If the answer is good and helpful, mark it as the best. 

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tq hermioneG
what about forest effect on environment
I have mentioned about deforestation, and also, you have provided points on the effects of forests on the environment, so I did not mention it again.
thanks for saying answer,,,
The Brainliest Answer!
There is a lot of impact on human activities on the environment because due to pollution and release of CO2 increase in global warming and rise int he sea level flooding can be happen
and industries contaminating the seas and rivers by throwing their wastage chemicals in to sea and killing sea animals
and cutting tress in forest and make their benefits
and their will be lot of changes in climate if you remove trees from  forest
wastage of water will also effect in the environment
no rains will happen and agriculture can be totally damaged
and their is a impact on the ozone layer

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