Global Temperature Graph

This is a graph showing global temperature over 1,030 years, approximately from 1880 to 2010. Each mark shows ten years. The vertical axis shows the temperature. Each mark on it is one tenth of a degree Celsius, from -.4 to .6 (one degree total). The graph shows the mean for each year and the mean for every five years. The page it came from says the data came from “air and ocean data from weather stations, ships and satellites” and also that it came from NASA. 

Global Warming/Global Temperature

These are some questions about global temperature. I have no idea what the answers are so I'm guessing at what I think.

What do you think the global average temperature is? I have no idea what the global average temperature is, because there are so many different areas with very different temperatures, but I'm guessing it might be between 40°F and 80°F, definitely less than 80°.

How much do you think the average global temperature has increased in the past 100 years? In the past 100 years I think the global temperature might have increased 10-20 degrees or less.

What do you think is the hottest the Earth has ever been?How about the coldest the Earth has ever been? I think the hottest the Earth has ever been might be around 80°F or higher. The coldest is probably below -1 to -10°F because of the ice ages.

Are you concerned about "global warming?" I am a little concerned about global warming because it could change a lot of things, but I'm not sure if it will happen while I'm alive or not.

Grassland soil and forest soil

Apparently, if an area has a lot of rainfall, it can have forest soil, but if it doesn't get as much rain that makes it a grassland soil. This is because if an area has a lot of rain, it makes very good soil and trees can grow there. It's wet enough in these areas so trees can survive. In grassland areas, there might be enough rain to produce good soil, but only enough so that grass can grow. Grass doesn't need as much water as trees, so if there is less rain trees can't grow, but grass will, making it a grassland. More water in an area means that the rocks weathers more quickly and forms more topsoil faster, which is better for growing things.