c. Climate change is a significant and persistent change in an area's average climate conditions or their extremes. Seasonal variations and multi-year cycles (for example, the El Niño Southern Oscillation) that produce warm, cool, wet, or dry periods across different regions are a natural part of climate variability. They do not represent climate change.

This multi-part activity introduces users to normal seasonal sea surface temperature (SST) variation as well as extreme variation, as in the case of El NiÃo and La NiÃa events, in the equatorial Pacific Ocean. Via a THREDDS server, users learn how to download seasonal SST data for the years 1982 to 1998. Using a geographic information system (GIS), they visualize and analyze that data, looking for the tell-tale SST signature of El Nino and La Nina events that occurred during that time period.

This short video clip summarizes NOAA's annual State of the Climate Report for 2009. It presents a comprehensive summary of Earth's climate in 2009 and establishes the last decade as the warmest on record. Reduced extent of Arctic sea ice, glacier volume, and snow cover reflect the effects of rising global temperature.

This NOAA visualization video on YouTube shows the seasonal variations in sea surface temperatures and ice cover for the 22 years prior to 2007 based on data collected by NOAA polar-orbiting satellites (POES). El NiÃo and La NiÃa are easily identified, as are the trends in decreasing polar sea ice.

This animation illustrates how the hardiness zones for plants have changed between 1990 and 2006 based on an extensive updating of U.S. Hardiness Zones using data from 5,000 National Climatic Data Center cooperative stations across the continental United States.

In this activity, students use Google Earth to explore global temperature changes during a recent 50 - 58 year period. They also explore, analyze, and interpret climate patterns of 13 different cities, and analyze differences between weather and climate patterns.

In this activity, students reconstruct past climates using lake varves as a proxy to interpret long-term climate patterns and to understand annual sediment deposition and how it relates to weather and climate patterns.

This is a video overview of the history of climate science, with the goal of debunking the idea that in the 1970s, climate scientists were predicting global cooling.

In this 3-part lesson, students explore California climate and factors that are leading to changes within this climate system. Students begin by exploring California's climate and the state's topography. Next, they investigate coastal versus inland climate. Finally, they use My NASA Data to explore the effects of El NiÃo/La NiÃa on two locations found at the same latitude.

This gallery of ten temperature graphs shows global temperatures on different timescales from decades (recently measured temperatures) to centuries (reconstructed) to millions of years (modeled from ice cores).

In this video clip, Climate Central's Dr. Heidi Cullen explains that what we've known as "normals" for our climate, during the past decade, will very likely change soon. The new climate normal will provide key information for decisions we make in the future, ranging from what we plant, to what we pay for energy, and even to where we take a vacation.