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Teaching about climate variability is supported by seven key concepts:

a. Climate is determined by the long-term pattern of temperature and precipitation averages and extremes at a location. Climate descriptions can refer to areas that are local, regional, or global in extent. Climate can be described for different time intervals, such as decades, years, seasons, months, or specific dates of the year.

Climate changes for many reasons, and on many different time scales.

These key ideas illustrate the differences between weather and climate and unravel some of the processes that cause natural climate variability, and abrupt climate change, and human-caused climate change. Understanding climate variability such as the El Niño/Southern Oscillation is critically important in helping scientists tease apart natural variation from human-induced climate change. In this principle the human impact on the climate through burning of fossil fuels is clearly differentiated from naturally occurring climate processes.

These ideas help sort out different ways that climate can change

Students frequently conflate weather with climate. While related, weather occurs over short (hours to days) time scales, and climate occurs over seasons and longer time spans. Because of these common confusions, it is especially important to clarify topics such as:

  • A spell of unusually cold or warm weather neither negates nor confirms human-caused climate change. Climate is defined as a long-term pattern with naturally occurring variability.
  • The climate has changed throughout the history of Earth, to varying degrees, over different time periods and due to different causes.
  • Human-caused warming is not the same thing as Earth's "natural" warming. Scientists use many lines of evidence to differentiate human-caused changes from natural cycles.
  • Weather and climate can both vary to a large degree over very small distances.

Helping students understand these ideas

A helpful starting point is to establish the difference between weather and climate. Weather events occur over minutes to hours to weeks, while climate is a longer-term pattern that plays out over seasons, years and into millennia. Both can change abruptly, but the reasons for the changes are often very different.

Understanding natural climatic processes that drive multi-year cycles (like the El Niño/Southern Oscillation) requires an understanding of basic climatic patterns and processes as well as feedback effects. Once students can appreciate the complexity of the climate system they will be able to understand that global warming doesn't necessarily result in warming at every location but that some (few) places might experience a net cooling despite the global trend of rising temperatures. Likewise, the occurrence of brief periods of cooling during a long-term trend of warming does not negate the fact that the climate is indeed warming.

The single most common misconception in the public's understanding of climate change is that the climate has changed in the geologic past, which some people incorrectly extrapolate to mean that humans cannot affect the climate today. Regardless of a student's mastery of climate science in class, they are virtually guaranteed to encounter this misconception outside of class. Educators can be pro-active in developing a robust understanding of these concepts and reinforcing them with multiple types of learning activities.

A related misconception is that humans cannot fix climate change. But if we know that the climate becomes warmer due to the addition of greenhouse gases, then we also know that adding less of them will reduce this effect. It is important to avoid a sense of hopelessness. These ideas are further discussed in Humans can take action, the guiding principle of climate literacy.


Bringing these ideas into your classroom

The two most basic cycles—the diurnal cycle and the annual cycle—are great places to begin exploring variability of weather and climate over time and space. Beyond these basic concepts, students can learn about climate variation on longer time scales, and how some changes are cyclic and others are not. These topics also afford the opportunity to present the key differences between weather and climate

It can be difficult to describe processes that operate on different time scales. Specific strategies that can help students understand this are using visualizations and teaching with simulations. Both of these approaches allow students to "observe" a process at work and get an overview of complex processes and relevant feedback loops.

A third concept that can enrich these ideas is to describe how scientific evidence can illuminate things that happened long ago. Scientific principles from geology, paleoclimatology, and atmospheric science have been used together to understand how climate systems have responded to changes on Earth in the past.

Teaching materials from the CLEAN collection

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What's Really Warming the World? - This animated graphic compares different forcings that are acting on Earth's climate. Climatic changes caused by orbital variation, the sun's luminosity, and volcanic emissions are compared with the effect of greenhouse emissions. The graphic is very engaging and the data is from NASA's Goddard Institute for Space Studies (GISS).

Climate Science Supplement from the 2014 National Climate Assessment report offers a thorough but readable explanation for both natural and human-caused changes in the climate system. Contains appealing diagrams that can be downloaded and reused for slides and handouts.

NASA Website about Difference between Weather and Climate - Summary written for a lay audience and supported by some NASA graphs.

NCAR Website about Difference between Weather and Climate- brief summary written for a lay audience.

The Biggest Control Knob: Carbon Dioxide in Earth's History by Richard Alley, presented at AGU in 2009, this video steps viewers through the geologic evidence for the role of CO2 in driving Earth's climate. Dr. Alley is an engaging and entertaining speaker.

What does past climate change tell us about global warming? This page from the Skeptical Science website provides clear answers to common questions and misunderstandings about climate change.

Additional Resources

Video about this Principle

Inclusive Climate Teaching Guidance