I am writing a novel about a pandemic, and the research for it has been fascinating and terrifying.
As people continue to overpopulate the Earth, we come into contact with animals who have been harboring diseases for possibly thousands of years, but those diseases might do the hosts no or little harm. But when we catch these diseases, they can kill us. (In a few cases, like cholera, what we see as a pathogen had a beneficial effect to its host.) People are afraid of bioterrorism...but the truth is, we don't need to be afraid of a "them" giving us diseases, for we are doing pretty darned well at doing that to ourselves.
For instance, with Machupo, a South American hemorrhagic fever, it was cutting down forests to plant monoculture farms (monoculture, the planting of a single crop, exacerbates this problem everywhere) to sell in town, when the traditional ways they made a living were taken from them. This put people in contact with mice who carried the disease and who found their way into villages they'd never before visited. The act of the morning sweeping of the home, which sends pulverized mouse droppings into the air, can infect people.With some diseases, when that infected person goes to town, he passes it on to a dozen other people, and eventually an infected person will get on an airplane, and the disease can move around the globe in a day.
It's happening in the U.S. and Australia too, so we can't think it's some sort of thing that only occurs in South America or Africa. Our own overpopulation is putting us close to animals that carry "new" diseases. (New to us, at least.) As we drive more delicate birds to extinction, opportunist birds like crows, robins, pigeons (here in North America) take over, and their droppings or saliva get on our things. We might wash our car or mow our yard and get the disease. Or a mosquito might bite a crow and bite us, and now we're ill. West Nile Virus is such a disease, carried in some crows.
You hear people sneering and saying, "Why should I care about the extinction of some damned owl?" So here's another reason to care. Because we're finding out more and more that some of these endangered animals controlled a pest, or kept an infected species in balance. So for those who can only think selfishly, that's why you'd care. Because you don't want to die by drowning in your own fluids, or crapping yourself to the point of dehydrating yourself to death, or by bleeding out of your eyeballs, which could well be the eventual punishment for such a cavalier attitude about the balance of nature.
Why should you care about saving the wetlands? Same reason. It provides a home for species that might be controlling a disease we don't even yet know is out there. When you're watching a grandchild die of one of those diseases, and you learn this is the case, might you not feel ashamed of your sneering about "save the wetlands" campaigns? (Probably not, I fear. People who do a lot of sneering at good works tend to never look in the mirror and admit wrongdoing and responsibility for their own tragedies.)
Mother Nature is full of dangers, but that's no reason to hate Nature and try to wreck eons-long balances she has developed. To save ourselves, and our children, we need to tread more carefully. We need to begin by practicing zero population growth, personally. For those who can afford to eat organic, local food grown at farms that produce several crops, that ameliorates the problem, too. Factory and feedlot meats, with the antibiotic overuse, contribute to antibiotic resistance to bacterial disease, so if you can afford antibiotic-free meat, buy that.
And when the day comes--and I guarantee you it will--that a killer pandemic is sweeping across the land, and the CDC (or the equivalent in your nation) says, "Stay home. Wear a mask. Wash your hands," do that, and without whining.
And think long and hard before you get on an airplane. If it's for a vacation, I'll bet you there are pleasant places to visit within driving distance, where the only diseases you are breathing in are the ones your family might already have.