NASA's Jet Propulsion Laboratory has an educational site about global climate change. It presents key indicators as well as evidence, causes and effects of our changing climate. The information is gathered from more than a dozen Earth science spacecraft and instruments in orbit studying Earth's systems. Some of the data has been tracked for decades while other information has only just begun to be studied.
The information is sobering, while we understand human activity has accelerated the natural progression of Earth's climate, there remains no clear answer on exactly what the result will be or how much of the consequences can be averted. Encouraging signs can be found, like reduced levels of ozone depletion thanks, in part, to accords reached in the 1987 Montreal Protocol.
One interesting feature of the website is the Climate Time Machine. It visually illustrates the changes in our climate as evidenced by yearly changes in things like polar ice, sea levels and average global temperature.