Scientist Janine Bloomfield says that samples taken from around the world show a significant increase in average temperatures. Click either the 28k or 100k button to view the video. Seeing the Changes Scientists who study global warming have tracked changes that have occurred over the past decades and centuries. Almost all scientists agree that global temperature and CO 2 rates are rising. However, not all of them agree on the extent of the problem and its causes.
Some scientists question the data that is being studied.
Some believe that we need to look at data that covers a longer period of time. Some question the degree to which humans are contributing to the problem. And there are some that question the severity of the consequences. Still others suggest that the recent increase in temperatures is merely the high point of a natural warming and cooling cycle. The science of climate change has also become a controversial political issue.