Icebergs floating near Cape York, Greenland
Mila Zinkova

Climate Change

Climate change refers to changes in global or regional climate determined over a long term - typically a minimum of 30 years. Individual short-term weather events such as an intense storm or heat wave are a normal aspect of weather variability, and are not a sign of climate change. Even several weeks of unusual weather conditions are not sufficient to prove that climate is changing. Evidence of a changing climate is found by looking at long-term averages of atmospheric data, over 30 years or more. When we see changes in atmospheric conditions over these long term intervals, we see evidence of a changing climate. 

While weather can change very quickly, in hours (and sometimes minutes!), climate changes over longer time frames depending on changes in the factors that determine Earth's climate. Earth's climate changes when there are changes in the energy received at Earth from the Sun and when there are changes in the amount of energy that is held in the Earth system. Changes in these factors occur over long-term intervals - decades or more. There are numerous ways in which these factors can change over the long term - ranging from changes in the amount of greenhouse gases in the atmosphere to small variations in the tilt of the Earth's axis - and Earth history demonstrates multiple intervals when our climate was very different. 

Because long-term weather conditions effect the type of plants and animals that live in regions on the planet, changes in climate can have significant effects on many aspects of life on the planet. In addition to changing atmospheric temperature, changing climate influences precipitation, winds, the intensity of storms, the persistence of ice, sea level, the temperature of water bodies, the distribution and survival of plant and animal species, and the distribution of disease. These, in turn, can have dramatic impacts on how our society functions. 

Today, thousands of climate scientists around the world are studying how the Earth's climate is changing. This large scientific community has been studying Earth's climate for decades, thanks to advances in scientific understanding, computing, and modelling. However, climate science is not new - over one hundred years ago scientists recognized that humans could influence the Earth's climate through the growth of greenhouse gases in the atmosphere. 

The scientific consensus today is that Earth's climate is changing, and that the cause of the change is the accumulation of greenhouse gases in the atmosphere produced mainly by the consumption of fossil fuels by humans to power our society. A wider community of specialists studies the potential impact of changing climate on Earth's ecosystems, economy, and society. Climate models are an important tool which can be used to examine future climate scenarios, based on assumed levels of greenhouse gas production driven by our consumption choices.

Last modified August 21, 2013 by Roberta Johnson.

You might also be interested in:

Cool It! Game

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

Earth's Global Climate

Earth's climate is determined by the amount of energy received from the Sun and the amount of energy held in the Earth system - in short, Earth's radiation budget.  The Sun emits a tremendous amount of...more

Regional Climate

The climate at a given location on Earth is the regional climate.  Regional climate depends on the temperature, precipitation, and winds experienced over the long term at that location. These characteristics...more

Earth's Greenhouse Gases

Less than 1% of the gases in Earth's atmosphere are called greenhouse gases. Even though they are not very abundant, these greenhouse gases have a major effect. Carbon dioxide (CO2), water vapor (H2O),...more

Kingdom Plantae

Though not the largest kingdom, with a mere 300,000 species catalogued, many might argue that the Kingdom Plantae just may be the most important group of living organisms. In the process known as "photosynthesis",...more

Effects of Climate Change Today

The world's surface air temperature increased an average of 0.6° Celsius (1.1°F) during the last century according to the Intergovernmental Panel on Climate Change (IPCC). This may not sound like very...more

Modeling the Future of Climate Change

Predicting how our climate will change in the next century or beyond requires tools for assessing how planet responds to change. Global climate models, which are run on some of the world's fastest supercomputers,...more

What is Climate?

Climate in your place on the globe is called regional climate. It is the average weather pattern in a place over more than thirty years, including the variations in seasons. To describe the regional climate...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA