# Climate Change Part of the Sustainability Merit Badge Digital Resource Guide: [Introduction & Overview](https://merit-badge.university/merit-badges/sustainability/guide/index.md) *7. Global Challenges* > **7f.** Find a world map that shows the pattern of temperature change for a period of at least 100 years. Identify three factors that scientists believe affect the global weather and temperature. Discuss how climate change impacts sustainability of food, water, or other resources. ## Temperature Change Over 100+ Years NASA and NOAA maintain detailed records of global temperatures dating back to 1880. These records show a clear pattern: Earth's average surface temperature has risen by about 1.1°C (2°F) since the late 1800s, with most of the warming occurring since the 1970s. World maps showing temperature change over time — called **temperature anomaly maps** — use color coding to show which regions have warmed and by how much. Key observations from these maps: - **The Arctic has warmed faster than any other region** — about two to three times the global average - **Land areas have warmed faster than oceans** — because water absorbs heat more slowly - **Every continent shows warming** — there is no region that has cooled over the past century - **The most recent decade was the warmest on record** — each of the last several years has ranked among the hottest ever measured > **Tip** > > NASA's "Global Temperature" page has interactive maps showing how temperatures have changed decade by decade. NOAA's Climate.gov also has excellent visualization tools. Use one of these for your counselor discussion — being able to point to a specific map makes your explanation much stronger. ## Three Factors That Affect Global Temperature ### 1. Greenhouse Gases Certain gases in the atmosphere — primarily carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) — trap heat from the sun like a blanket around Earth. This is called the **greenhouse effect**, and it is natural and necessary — without it, Earth would be too cold for life. The problem is that human activities have dramatically increased the concentration of these gases: - **CO2** has risen about 50% since 1750, mainly from burning fossil fuels and deforestation - **Methane** has more than doubled, from livestock, rice paddies, landfills, and natural gas leaks - **Nitrous oxide** has risen about 20%, from agricultural fertilizers and industrial processes ### 2. Solar Activity The sun's energy output varies slightly over an 11-year cycle (and over longer periods). During periods of higher solar activity, Earth receives slightly more energy. However, solar changes account for only a small fraction of the warming observed since 1900 — scientists estimate solar activity explains less than 10% of recent temperature changes. ### 3. Volcanic Eruptions and Aerosols Major volcanic eruptions inject sulfur dioxide and ash into the upper atmosphere, where they reflect sunlight and temporarily cool the planet. The eruption of Mount Pinatubo in 1991 cooled global temperatures by about 0.5°C for roughly two years. Human-produced aerosols (tiny particles from burning coal, diesel, and other fuels) can have a similar cooling effect by reflecting sunlight. Ironically, cleaning up air pollution — while great for human health — may slightly accelerate warming by removing this cooling mask. > **Did You Know?** > > The last time CO2 levels were as high as they are today (over 420 parts per million) was about 3 million years ago, during the Pliocene Epoch. At that time, sea levels were 50–80 feet higher than today and the Arctic was forested. ## Climate Change and Sustainability Climate change is not a separate problem from sustainability — it is woven into every aspect of it. Here is how it affects key resources: ### Impact on Food - **Crop yields** decline when temperatures exceed optimal growing ranges - **Droughts and floods** destroy harvests and disrupt planting seasons - **Pest ranges expand** as warmer temperatures allow insects to move into new areas - **Pollinators are disrupted** as flowering seasons shift out of sync with pollinator lifecycles ### Impact on Water - **Glaciers and snowpack** that provide freshwater to billions of people are shrinking - **Drought intensity and duration** are increasing in many regions - **Flooding** is becoming more severe as warmer air holds more moisture - **Sea level rise** threatens freshwater supplies in coastal areas through saltwater intrusion ### Impact on Other Resources - **Forests** face increased wildfire risk, pest outbreaks, and heat stress - **Fisheries** are disrupted as ocean temperatures and chemistry change - **Energy systems** are strained by increased cooling demand and extreme weather damage - **Infrastructure** (roads, bridges, buildings) is damaged by extreme heat, flooding, and storms > **Safety First!** > > Climate change is increasing the frequency of extreme weather events — heat waves, hurricanes, wildfires, and severe storms. Stay informed about weather conditions in your area, especially before outdoor activities. Know your community's emergency plans and have a family preparedness kit ready. ![A stylized globe showing temperature change patterns over 100 years, with color gradients from blue (cooler) to red (warmer), with the Arctic showing the most intense warming](https://ik.imagekit.io/doulacoop/tr:w-800/mbu-assets/merit-badges/sustainability/guide/temperature-change-globe?v=f7fbbc9c) [NASA Global Climate Change — Vital Signs](https://climate.nasa.gov/): NASA's comprehensive resource on climate change, featuring interactive data visualizations, temperature records, and the latest research findings. Video: [Global Warming from 1880 to 2022](https://www.youtube.com/watch?v=LwRTw_7NNJs) --- - Previous: [Species Decline](https://merit-badge.university/merit-badges/sustainability/guide/req7e/index.md) - Next: [Campout Observations](https://merit-badge.university/merit-badges/sustainability/guide/req8a/index.md)