For example, scientists are intensively investigating the interactions of water vapor, clouds, oceans, and sea ice in the global climate system in order to refine their computer models. In addition, scientists are continuing to work to pin down the likely impact of global warming on plant ecosystems, since higher carbon dioxide levels, higher temperatures, and changed precipitation patterns would have complicated effects on particular cultivated crops and forest communities. In general, scientists need to know more about how the climate would change region by region and what the regional and local consequences of climate change would be. Virtually all scientists agree that more research is needed to answer such questions and to improve scientific understanding of global warming. As research progresses, current climate projections will continue to be refined.
Historical records show that the climate has changed in the last one hundred years.
The 10 warmest years since 1860 have all been since 1980. Sea level has risen between 3.9 and 10 in. The mean annual air temperatures of Antarctica have increased steadily since the 1950s. Thus, the evidence of a statistically unusual change in climate has recently become more compelling. But the more important issue the Intergovernmental Panel has to address is whether this change can be attributed to human activities.