Lets just think real quick about a feedback loop of sorts here.
* Without humans, the earth does a pretty great job of keeping everything stoic. There are volcanoes, ice ages, rainy periods, droughts, etc, yes! But some of these main evens come and go over millions of years.
* The earth breathes and recycles itself pretty efficiently, not by design, per se, but by evolution. Algae in the ocean create some 70% of the oxygen. The amazon sequesters C02 and spits out more oxygen. Animals breathe in the oxygen, and left unfettered, aid in recycling organic matter, allowing the soils to remain healthy as they graze and move around.
Insert humans.
As one chain of examples:
Humans chop down portions of amazon. This uses resources to build the machinery, get the machinery there, and do the work.
Biodiversity begins to plummet, pragmatically.
The trees are removed. Trees are essentially tons of stored and sequestered carbon from the atmosphere. These are removed. If burned, all of that carbon is released into the atmosphere. The remaining trees get split up, probably wrapped in plastic or combined with other materials to be turned into something else. Plastic, of course, is made from long polymer chains, or oil, essentially.
In the same spot, the soil is repurposed for, say, soy bean farms for cows, or actual car pastures. The soil is treated with nitrogen and fertilizer. This makes the soil unable to sequester carbon and actually begins to release more carbon. Of course the cow farts and burbs release tons of methane into the atmosphere as well. Not to mention, humans eating the meat, and creating our own methane, and left over rancid meat rotting away again releases more methane and other greenhouse gasses.
Whats left of the site that took down a portion of the rainforest is now a wasteland of sorts. What's left of the amazon does a less of a good job at helping the earth breathe. This causes droughts upstream and sequesters less and less C02. Plastic and other waste such as fertilizer and manure from the site runs off into the ocean, which kills oxygen producing algae. This aids in causing a warmer ocean. A warmer ocean Is all that a hurricane needs to become stronger and create more havoc when it lands on our coasts. Warmer oceans also cause ice sheets to melt, which not only cause ocean levels to rise, but release more carbon which increases the warming we are experiencing.
You may notice not everything in this one example is a-b-c-d. This is because not everything works as humans intend in a clean systematic approach. We think we are just chopping down a tree, to start a farm or sell for money. But at the end, we are releasing carbon both in getting to, chopping down, removing the tree, transporting the tree to its factory, releasing C02 if we burn the tree, and if nothing else, not allowing the tree to be absorbed by the earth's natural fungal networks which help create healthy, c02 sequestering soil. Everything we do, it is turning out, tends to have many direct and downstream (indirect) effects. It all becomes part of the bigger picture. And the bigger picture is, from us having ~8 billion people, to individuals using plastic straws, to large corporations burning huge piles of tires, to having oil leaks in the ocean, to you fertilizing your backyard, to me driving my car, to using air conditioners, whether we eat meat or soy beans, humans are turning the earth from an anti-fragile, self-sustaining ecosystem to a fragile, rapidly self-depleting hell hole.