What are the three signs of global warming?

What exactly do you mean by "global warming"? During the American revolution, the Potomac River froze so solid that soldiers were able to ROLL their cannons across. Everybody has known very well that weather has been getting warmer since then. Weather scientists have known since 1940 that the USA was warmer than normal, and the abundance of crops was due to weather, not fertilizers or farm machinery. So we have 241 years of rising temps, and millions of years of repeating cycles of freeze and thaw, so if you think this is suddenly a problem, and a man made problem, you need to find some support for your position.