ENVIRONMENT
How do greenhouse gases cause atmospheric warming? Use our activity to find out.
Teachers, scroll down for a quick list of key resources in our Teachers Toolkit.

Photograph by Tinou Bao, courtesy Wikimedia. CC-BY-2.0
Discussion Ideas
- More than 170 nations have signed the Kigali Agreement, a “monumental” agreement to limit emissions from HFCs, a set of greenhouse gases. What are greenhouse gases? Use our short resource on the greenhouse effect for some help.
- Greenhouse gases are atmospheric gases that absorb solar heat reflected by the surface of the Earth, warming our atmosphere. Greenhouse gases include carbon dioxide, methane, water vapor, and ozone.
- Greenhouse gases let the sun’s light shine onto the Earth’s surface, but they trap the heat that reflects back up into the atmosphere. In this way, these naturally occurring gases act like the glass walls of a greenhouse. This greenhouse effect keeps the Earth warm enough to sustain life.
- Since the Industrial Revolution, people have been releasing large quantities of greenhouse gases into the atmosphere. The amount of CO2 in the atmosphere today, for example, far exceeds the natural range seen over the last 650,000 years. The emission of greenhouse gases is the leading cause of anthropogenic climate change.
- What are HFCs? Use our short resource on the greenhouse effect for some help.
- Hydrofluorocarbons (HFCs) are a type of fluorinated gas most often used as coolants in refrigerators and air conditioners, and in aerosol sprays.
- There are many different types of HFCs, sold under brand names such as Puron, Suva, and Genetron.
- HFCs came into common use after nations agreed to phase out CFCs, starting in the 1980s. (Chlorofluorocarbons were found to harm to ozone layer, while HFCs do not.)
- As a greenhouse gas, HFCs are “thousands of times more potent than CO2 on a pound-per-pound basis,” and the Kigali Agreement will remove the “equivalent of about 70 billion tons of carbon dioxide from the atmosphere by 2050.”
- Hydrofluorocarbons (HFCs) are a type of fluorinated gas most often used as coolants in refrigerators and air conditioners, and in aerosol sprays.
- The complex Kigali Agreement sets three pathways to reduce HFC use. What are they?
- The three pathways are largely defined by a country’s economic development.
- Wealthy, developed countries, such as the United States and the European Union, will start to limit their use of HFCs within a few years and make a cut of at least 10% from 2019.
- Rapidly developing countries, including many in Latin America, will freeze their use of HFCs starting in 2024.
- Developing countries, specifically India, Pakistan, Iran, Iraq and the Gulf states, will freeze their use starting in 2028.
- The three pathways are largely defined by a country’s economic development.
- Why do some supporters think the Kigali Agreement is “much, much, much stronger” than the Paris agreements of 2015?
- “[W]hile the Paris pledges are broad, they are also voluntary, often vague and dependent on the political will of future world leaders. In contrast, the Kigali deal includes specific targets and timetables to replace HFCs with more planet-friendly alternatives, trade sanctions to punish scofflaws, and an agreement by rich countries to help finance the transition of poor countries to the costlier replacement products. So … the new accord may be more likely to yield climate-shielding actions by industry and governments, negotiators say.”
- Why do some environmentalists think the Kigali Agreement “is a big deal, but it could have been bigger”?
- HFC emissions contribute far less to climate change than carbon emissions. (They are more potent, but less widely used.)
- Alternatives to HFCs have significant challenges: toxicity, price, flammability.
- Developing countries in hot regions with serious use for HFC-based air conditioners, such as the Gulf States, will not have to limit emissions for more than 10 years.
- China, the world’s largest producer of HFCs, will not start to cut their production or use until 2029.
TEACHERS TOOLKIT
Time: Countries Reach Landmark Deal to Limit Global Warming From Air Conditioners
BBC: Climate change: ‘Monumental’ deal to cut HFCs, fastest growing greenhouse gases
New York Times: Nations, Fighting Powerful Refrigerant That Warms Planet, Reach Landmark Deal
Nat Geo: Interactions Within Earth’s Atmospheres activity
Nat Geo: What is the Greenhouse Effect?
Reblogged this on Ripper's Chatter and commented:
Another great resource, Enjoy 🙂