Extinction is when an entire species is killed. It is sometimes caused by pollution, or natural means, but most of it has been done by us. There are two other categories of extinction: expiration (local extinction), and extinct in the wild.
Global Warming is the process of the Greenhouse Gasses, for instance, CO2, being dumped in the atmosphere and warming up the Earth. Over time, the Earth will increase in temperature until it is no longer habitable, leading to our own extinction. The problem is that we are polluting the seas, deforesting the forests, which causes lots of CO2 to enter the atmosphere, when it otherwise would be absorbed by the plants in the area.
Pollution is the process of putting waste into a perfectly good environment, most likely destroying habitats in the process. It decreases biodiversity in the destroyed habitat. Speaking of biodiversity...
Biodiversity is the number of species divided by the number of organisms. Say we have a lush rain forest. Its biodiversity might be 35%, so for every 100 organisms, there would be 35 species. In a field of corn, the biodiversity would be 1%, so there would be only one species per one hundred organisms, being all corn.
The process of removing a forest. It destroys animal habitats and destroys biodiversity. Not only this, but the Oxygen (O2) in the air is reduced, because forests turn Carbon Dioxide (CO2) into Oxygen.
Each have different processes, but they all end up in the same thing: an organism that we want for it's traits. Artificial Selection is the simplest to understand: we breed the animals for the traits that we want, and they get passed down to the next generation. Domestication is when a normally dangerous animal gets made into a pet or a tame animal. Dogs are a good example of domestication, as they come from wolves. Genetic modification is when we modify the genetics of an animal to hope it gets the traits we want. Either way, after any of these processes, no matter where the organism ends up, it becomes an invasive species, a species that is not native to an ecosystem.