The Extreme Weather pcMEL

The Extreme Weather pcMEL asks students to weigh the connections between evidence and alternative explanations about the relationship between extreme weather and climate change. Extreme weather is a critical environmental issue facing Earth and its inhabitants.

Below are links to resources that will help students use the Extreme Weather pcMEL and learn more about fundamental scientific principles related to climate and weather.


This article provides an introduction to the Extreme Weather build-a-MEL (baMEL). It is useful even if you are using the Extreme weather pcMEL with your students. The primary difference between the pcMEL and the baMEL is that with the pcMEL students are given two models and four lines of evidence in a preconstructed diagram where as with the baMEL students choose two models from three and select four lines of evidence from eight to create their own MEL diagram.

Extreme Weather Events Article Cover
Extreme Weather Events and the Climate Crisis (Acrobat (PDF) 223kB Feb8 21)

Next Generation Science Standards Performance Expectations

MS-ESS3-2: Earth and Human Activity

  • Analyze and interpret data on natural hazards to forecast future catastrophic events and inform the development of technologies to mitigate their effects.

HS-ESS3-4: Earth and Human Activity

  • Use a model to describe how variations in the flow of energy into and out of Earth systems result in changes in climate.

The Models

Model A: Increases in extreme weather events are linked to climate change. Current climate change is mainly caused by human activities, such as fossil fuel use.
Model B: Over time, increases and decreases in extreme weather events are mainly caused by changes in Earth's orbit around the Sun.

Student Handouts

Lines of Evidence

Evidence #1: Since 2000, there have been more intense, extreme, weather events around the world. Record rainfall fell in Europe. The southeastern United States had the most active month of tornadoes. The decade from 2000 to 2010 was the warmest ever during the past 1000 years.
Evidence #2: Frequency and size of large wildfires have increased in the Western U.S. since 1970. Average spring and summer temperatures have also risen in the Western U.S. during this time.
Evidence #3: In the last 100 years, global temperatures have increased. In that same time period, heavy precipitation events have also increased.
Evidence #4: Earth's orbit is elliptical. But, the shape of the ellipse is almost a perfect circle. In the Northern Hemisphere, Earth is slightly closer to the Sun in winter than in summer.

Student Handouts

Lateral Reading (LR) Resources

Use lateral reading to evaluate the credibility of two sources related to extreme weather.

What does it mean for a source to be credible? Why should we investigate whether a source is credible before we read it? How do we decide whether online sources are credible? We will use lateral reading to find out.

This LR Activity connects to Evidence #2 above: Frequency and size of large wildfires have increased in the Western U.S. since 1970. Average spring and summer temperatures have also risen in the Western U.S. during this time.

Use the LR Guiding Questions to evaluate the credibility of each source.

  • LR Guiding Questions (Acrobat (PDF) 28kB Jun8 23)
  • Source #1: The 2015 Wildfire Season Set an Ominous Record
  • Source #2: U.S Wildfires

Other Resources

This Plausibility Ranking Task (PRT), which may be completed prior to using any MELs, helps students to understand the role of evidence in supporting or refuting models.

Virtual MEL

The Google Drive folder below contains MEL resource documents in the Google formats. In order to maximize the flexibility of our activities, the MEL Project Team wanted to make more resources compatible with virtual settings. We have made our MEL scaffolds available in Google formats, so that they can be copied, modified, and uploaded more easily on a variety of platforms and devices. Please note that to access all the materials for each MEL scaffold, you will need a Google account. View the README file first.

Digital Resources

Extreme Weather NCA
This site on Extreme Weather from the National Climate Assessment provides an introduction to extreme weather events, including heat waves, droughts, heavy downpours, floods, hurricanes, and other storms.