As particular environmental concerns became prominent, systems of measurement were put into place to provide the needed information. The interest in temperatures and rainfall led to the establishment of national weather bureaus, which then proceeded to add other dimensions as demands arose. Some of the data systems use relatively simple instruments and training, as with the thousands of amateur observers around the United States who report daily measurements. Others are highly sophisticated, such as the satellites that furnish the images that record the approach of tropical hurricanes. Some need to be global because the phenomena being investigated and recorded occur on a global scale—for example, satellite measurements of stratospheric ozone.

Although the desirability of directly comparable measurements has long been recognized, the great majority of environmental data collected over the last several decades fails to meet this criterion. Most scientific environmental research has the primary goal of understanding a particular system at one time and in one place, and only later and separately does the question of whether this understanding is substantially different in another place or in the same location at some future time arise.

Environmental monitoring has been going on in a quantitative instrumental manner since before the 1870s. In general, the development of research efforts in long-term environmental monitoring originated first in the geophysical sciences and only much later spread to the biological sciences.