AMS Climate at a Glance Application

Statistical analyses can help you tell if observed changes in temperature and precipitation are due to climate variability or climate change

NOAA succinctly defines climate change as “a long-term shift in the statistics of the weather (including its averages).” Climatologists generally rely on 30-year averages of climate elements, updated at the beginning of each new decade—called climate normals—as a basis for describing the statistics of a location’s climate. Climate data exhibit year-to-year fluctuations above or below these long-term averages. This variability occurs whether or not climate change is taking place.With these ups and downs continually occurring, how do we know when climate change has actually taken place? 

The tool makes it easy to explore statistics that can reveal whether differences in two groups of data are likely to be due to random variability or to other factors. If the comparison of two non-overlapping 30-year climate data sets from the same location determines they are statistically different, more than random chance is involved and it can be assumed climate change has taken place. Learn more about the tool