What can an ordinary person do?

a lot, as long as youre not 4ft5 or you had hip surgery like me

If you really want to help....Join the millions of men and women in the United States that purchase hunting licenses, permits and tags. Every penny generated by these purchases goes toward wildlife management, conservation and preservation of wild habitats. Not to forget this money also pays the salaries of 680,000 men and women directly involved in the wildlife and environmental preservation industry.

The purchases from the hunting community also support the economic growth of sporting goods retailers as well as their respective communities. Hunters generate "Billions of Dollars" annually for wildlife and habitat conservation.

we can see the footprint of polar bear everywhere,don't worry,

Polar Bears are thriving. Don't worry about them.

The problem is too large for one person to really do anything that will matter on a global scale, but lots of people, as a group, can make noise and get heard and maybe even get something done. You can't solve the world's problems alone, you will have to join with like-minded people if you want an impact.

This does not mean it is futile, not at all worth the trouble, to live your life doing good around yourself. Just the opposite. You have to live your life doing whatever you can to help reduce the problem. If that involves picking up loose plastic along the seashore, well, that is a few less pieces of plastic that end up in the ocean. If you clean up the roadside, well, that is a bit less waste that affects woodland creatures.

All you can do is the best that you can do. Every little bit helps even if any little bit does not get rid of the problem. And this is true of pretty well anything. If you see something that you feel is wrong, speak up. If you see a problem, try to fix the part you can. Try to get others to fix the parts they can.