Climate Reporting: Roots of Climate Research in Weather

NOAA's research laboratories, Climate Program Office, and research partners conduct a wide range of research into complex climate systems and how they work. NOAA researchers monitor the Earth's atmosphere to provide clues about long-term changes in the global climate. Climate modeling done by NOAA researchers aids our understanding of, and ability to forecast changes in, complex climatic systems.

Imagine you are watching TV and the weatherman appears and says, "Today, we are going to experience cloudy skies in the northeast, rain in the southwest, and sunshine in Sacramento." Is he talking about the weather, or is this climate? What is the difference?

Look out the window: What you see today is weather. What you see on average is climate.

Weather is the day-to-day changes in the state of the atmosphere, whereas climate is the long-term average of weather. Understanding the difference between climate and weather is important because changes in climate imply that the range of day-to-day weather has also changed. For example, if the climate of a given area warms over a period of several decades, it may imply an increased frequency of heat waves, which has large socioeconomic impacts.

The scientific community now recognizes that in addition to accurately forecasting day-to-day weather hazards, assessing and predicting current and future climate change is a high priority to the global community at large. However, climate and weather science have not always been distinct entities.

This article looks at the history of climate research at NOAA, and illustrates how this research has evolved from its early dependence on weather into a separate discipline.


The Weather-to-Climate Research Transition

In addition to information about past climate conditions derived from tree rings, ice cores, and lake-bottom sediment cores, initial observations for climate research were derived from instruments used for weather research. These observations were then later methodically collected and analyzed for use in climate research. Early climate research efforts were, in many instances, a byproduct of tools that were used to track weather, not climate, and thus the roots of climate research lie in the early connection between weather and climate research.

It was not until 1873, following the creation of the International Meteorological Organization (the present-day World Meteorological Organization, or WMO), that climate research branched from weather into its own genre. WMO's efforts enabled scientists to standardize meteorological observations, which allowed observations collected around the world to be directly compared and used together.

One of the first climate research advances came in 1873, when a German climatologist named Wladimir Koppen averaged annual weather observations collected between 1820 and 1871 from 100 different weather data stations. This WMO data revealed that changes in weather corresponded with large-scale changes in climate. Koppen's work helped fill the gap between climate and weather research.

Later, an Englishman named G.S. Callendar assisted in distinguishing weather research from climate research. By compiling monthly temperature, precipitation, and pressure data from hundreds of stations around the world from as far back as the early 1800s, Callendar was able to explain the influence of carbon dioxide on temperature and in producing a globally-averaged temperature.


Climate Research Begins in the United States

This is a cooperative weather station in Granger, Utah, circa 1930.

The National Weather Service Cooperative Observer Program, or “COOP,” was created in 1890, at the same time that the NCDC was created. COOP was established to provide observational meteorological data and also help measure long-term climate changes. The COOP is the nation’s weather and climate observing network of, by, and for the people. This is a cooperative weather station in Granger, Utah, circa 1930. Click image for larger view.

Accomplishments around the globe illustrated the need for the U.S. government to begin compiling information to understand climate, not just weather. Thus, in 1890, the National Climatic Data Center (NCDC) was created through a Congressional order to "establish and record the climatic conditions of the United States." The NCDC housed and disseminated vast amounts of weather and climate data.

Early Attempts to Understand Atmospheric Gases and Climate

With the creation of the NCDC came further attempts to understand climate. In 1824, Joseph Fourier found that gases in the atmosphere might increase the surface temperature of the Earth. In 1859, John Tyndall discovered the differences in the abilities of gases and vapors to absorb and transmit heat from the sun. He found that gases such as oxygen, nitrogen, and hydrogen absorbed little radiant heat, while more complex gases absorbed more heat than the atmosphere itself.

In 1859, John Tyndall discovered the differences in the abilities of gases and vapors to absorb and transmit radiant heat.

In 1859, John Tyndall discovered the differences in the abilities of gases and vapors to absorb and transmit radiant heat. Click image for larger view and image credit.

This research eventually led scientists to conclude that ozone (composed of three molecules of oxygen) absorbs 80 percent of the sun's radiated heat. Most notably, laboratory experiments to understand carbon dioxide and its affects on the atmosphere were conducted in the late 1800s.

The Long-term Greenhouse Gas Record

historical sign at the Mauna Loa Observatory - Geophysical Monitoring for Climatic Change.

In 1958, Charles (Dave) Keeling pioneered measurements of carbon dioxide at the Mauna Loa Observatory. Above is the historical sign at the Mauna Loa Observatory - Geophysical Monitoring for Climatic Change. At the Observatory, carbon dioxide in the atmosphere has been measured for many years. Click image for larger view.

The accomplishments of the 19th century provided the perfect environment to make strides in climate research. In 1958, Charles (Dave) Keeling began measuring carbon dioxide in Antarctica and at the Mauna Loa Observatory in Hawaii. Keeling's efforts allowed the government to monitor atmospheric greenhouse gases, namely carbon dioxide, across the globe. These measurements have continued to be collected under successive agencies responsible for U.S. weather-related activities, including the Environmental Science Services Administration in 1965, and NOAA starting in 1974.

The geodesic dome and skylab as seen from the old Clean Air Facility at South Pole Station.

The geodesic dome and skylab as seen from the old Clean Air Facility at South Pole Station. Click image for larger view.

Together, these continuous measurements provided the first unmistakable evidence of atmospheric carbon dioxide increase. They were precise enough to indicate a rise in concentration in 1959, when compared with the results of the previous year. Subsequent measurements have shown persistent increases annually.


These data were used for baseline measurements of trace gases in the atmosphere. It also showed the rate at which carbon dioxide levels in the atmosphere were rising. This contribution to our understanding of the carbon cycle and the increase in atmospheric carbon dioxide has provided a pivotal marker in the study of global climate change.


Modeling the Earth's Atmosphere

Realizing that major changes were taking place in the Earth's atmosphere, NOAA created the General Circulation Modeling Laboratory in Washington, DC, in 1955. This laboratory would later become NOAA's Geophysical Fluid Dynamics Laboratory (GFDL).

Scientists from GFDL created the first numerical model that represented the physical processes important to the long-term circulation of the atmosphere. This model gave NOAA the ability to assess how changes in solar radiation, clouds, and greenhouse gases may impact future global climate.

Numerical models, which are systems of mathematical equations derived from the basic laws of physics, are essential tools for understanding past, current, and future climate. Since we can not recreate the Earth's atmosphere in a test tube in order to run experiments, scientists use computer-based simulations to study the processes that drive climate. With their use, simulation has joined theory and observation as a pillar supporting scientific advancement.

Surface air temperature anomalies simulated in one of GFDL’s CM2.1 model’s projections for the 21st century. The annual mean temperature differences shown are for year 2100; the simulared global mean warming is 5.0° F.

Surface air temperature anomalies simulated in one of GFDL’s CM2.1 model projections for the 21st century. The annual mean temperature differences shown are for year 2100; the simulated global mean warming is 5.0° F. Click image for larger view.

The GFDL's original atmosphere general circulation model was the first of its kind. Although the model included all basic components of a climate model (atmosphere, ocean, land, and sea ice) it covered only one-sixth of the Earth's surface, from the North Pole to the equator and 120 degrees in longitude wide. The model was later used to simulate the first three-dimensional greenhouse warming experiment ever run.

Improved physical understanding of the climate system translates into better models. Better models translate directly into improved understanding and predictions of the behavior of the atmosphere, oceans, and the climate system. The next generation of models, Earth system models, go beyond the physical system to simulate the biological, geological, and chemical processes that affect global ecosystems.


Understanding Ocean-Climate Interactions

By 1970, scientists realized that the climate system was so delicately balanced - and nearly every feature of air, water, soil, or biology so sensitive to changes in any other feature - that a holistic approach was needed to understand the complex inter-relationships of these features. A better understanding of the oceans was especially critical, because the top few meters of the oceans hold more heat energy than the entire atmosphere.

NOAA's Atlantic Oceanographic and Meteorological Laboratory and Pacific Marine Environmental Laboratory launched extensive ocean-based observing programs to understand the role of the ocean in climate variability and climate change. The oceans are important reservoirs and transporters of climate variables such as heat and carbon dioxide. There is growing recognition that the planet's climate depends on feedback mechanisms that are difficult to prove. This is because any change in the climate system may result in changes that will either amplify (positive feedback) or dissipate (negative feedback) the original change, such as shifting wind patterns or melting ice sheets.

The development of extensive oceanic and atmospheric measurement programs and climate models gives scientists excellent tools to study and understand climate feedbacks.



Since NOAA's beginnings, weather and ocean research have been critical in the advances made in climate research. From the early stages, scientists have tried repeatedly to perfect climate research in an attempt to provide improved climate forecasts on timescales from seasons through decades; however, limitations in technology and resources have made such forecasts challenging.

Through continued exploration, NOAA and partners have been able to come closer to distinguishing the differences and linkages between climate research and weather research. As the climate community continues to build upon past success and failures, NOAA will continue to improve climate forecasts and assessments in order to mitigate the socioeconomic impacts of future climate change.

Contributed by Dondi Ojeda, NOAA's Office of Oceanic and Atmospheric Research