Climate varies over space and time through both natural and man-made processes.

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.

A 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, it is likely that they will encounter this misconception outside of class. Educators can be proactive 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. For more on climate change and mental health, see the CLEAN Climate Mental Health pages.

Bringing these ideas into your classroom

The two most basic cycles—the diurnal cycle and the annual cycle—are great places to begin exploring the 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

Middle school

• Students can use their home turf to understand variations of the climate in this data collection activity, Differences Between Climate and Weather.
• Atmospheric CO₂ at Mauna Loa Observatory illustrates current and historical data of atmospheric carbon dioxide from the late 1950s to the present. This web page always contains current data.
• Students receive data about tree ring records, solar activity, and volcanic eruptions to examine The Little Ice Age: Understanding Climate and Climate Change.
• Debunking Cranky Uncle on past climate change - This humorous short video uses the 'single-cause fallacy' to debunk the myth that current changes in the Earth's climate are a result of natural phenomena.

High school

• Nobody explains climate better than Richard Alley. The video CO₂ and the Atmosphere describes the multiple lines of evidence for the role of CO₂ in Earth's climate system.
• Back to the Future: Climate Edition - This activity engages students through an exploration using real data of paleoclimate proxies, such as ice cores, tree rings, and sedimentary analysis that provide evidence for past climates.
• The activity Normal Climate Patterns explores local climate data so that students can inform a pen pal what type of weather to expect during an upcoming visit.
• Understanding Global Change Interactive - This interactive module allows students and educators to build models that explain how the Earth system works. The Click and Learn application can be used to show how Earth is affected by human activities and natural phenomena.

College

• Climate Around the World offers a dynamic, poster-making approach to see how climate varies around the world. Could also be used in high school.
• What are the causes and effects of ENSO? - In this activity, students play the role of a policymaker in Peru to examine data and recommend actions.
• Students use Excel to compare carbon dioxide data from Mauna Loa Observatory, Utqiagvik, Alaska (also known as Barrow), and the South Pole over the past 40 years in The Modern Atmospheric CO2 Record.
• Students can plot long-term climate data with Vostok Ice Core with Excel.