Which of the following human activities will have the greatest effect on both local and global ecosystems?

Question

anonymous · Answer

absorption of chemicals released by the burning of fossil fuel into the natural cycles of Earth
 elevated atmospheric levels of CO2 due to the burning of carbon reactants
 release of exotic (non-native) species into local ecosystems
 widespread application of pesticides, insecticides, and herbicides on farmland

anonymous · Answer

I'm stuck between the second and last.

anonymous · Answer

The others seem local.  I believe that it would the last one due to it directly killing ecosystem organisms, but increased co2 levels are very global.

anonymous · Answer

Can you give me an answer and EXPLANATION.

anonymous · Answer

hi

anonymous · Answer

The elevated atmospheric levels of CO2 due to the burning of carbon reactants. if Carbon production is greater that it's usage, meaning there is no regulating it the effects will last for centuries. Icecaps will melt away and many organisms will disappear.

anonymous · Answer

what do you think?