How much of a problem do you think global warming is?

What do you think global warming is? What do you think will happen as the earth warms up? Will it affect you or your kids or your grandchildren? If so, how? Does the idea of global warming make you change your behavior? Or do you rely on other people to help you be green (like Toyota making hybrid cars, or other companies designing low-flow toilets, or developers building more housing close together instead of creating more suburban sprawl)?