In short: it is the natural process that warms the Earth’s surface.
The process is called the greenhouse effect because the exchange of incoming and outgoing radiation that warms the planet works in a similar way to a greenhouse.
Picture this: a greenhouse is so successful at growing plants year-round, even when it’s too cold outside for some plants to typically thrive. How? Because the air inside the greenhouse naturally stays warmer than the air outside.
A greenhouse is constructed of glass, allowing sunlight to penetrate the exterior and warm the air and plants inside. The heat that isn’t absorbed by plants is trapped by the glass and can’t escape. Throughout daylight hours, sunlight keeps coming through the glass, adding more and more heat energy so the inside gets warmer and warmer (and continues to stay warm after the sun sets).
The Earth and the Sun work in a similar fashion (on a much more massive scale and a different physical process). The sun shines through the Earth’s atmosphere and the earth’s surface warms up. Some of the Sun’s energy is reflected directly back to space, the rest is absorbed by land, ocean, and the atmosphere. The greenhouse gases in the atmosphere trap heat radiating from Earth toward space.
What is Global Warming? feat. Katharine Hayhoe
So, what is global warming? This adorable animation makes it super simple.Posted by Climate Reality on Saturday, June 4, 2016
But here’s where this process presents a problem:
Carbon dioxide, methane, and other “greenhouse gases” trap heat that would otherwise escape Earth’s atmosphere. In the right proportion, these gases do a critical job ensuring the atmosphere holds onto enough heat to support every kind of life on the planet. Without them, the Earth would lose so much heat that life as we know it would be impossible.
The problem arises when greenhouse gas levels get too high because of human activities, trapping too much of the sun’s energy as heat and upset the natural systems that regulate our climate. Things keep getting hotter and hotter and we start seeing more and more extreme weather and other impacts.
Even small changes in the global average temperature can cause major and dangerous shifts in climate and weather. Just consider the difference between 0 and 1 degrees Celsius (or 32 and 33 degrees Fahrenheit) – that one degree means the difference between ice and water.
Now imagine that difference happening regularly for months. Imagine it happening in a region that depends on a natural cycle of winter snow building up and precipitation in the spring, feeding streams and rivers and supplying farms and communities with the water they need for everyday life. And that’s just one example.
Plus, burning fossil fuels aren’t the only thing contributing to rising levels of carbon dioxide. Trees are often called the Earth’s lungs, thanks to their incredible ability to absorb and store carbon dioxide from the atmosphere. Deforestation – cutting down trees on a large scale for fuel, land, or other purposes – leads to more greenhouse gases in the atmosphere as more trees are burned and fewer are in the ground to absorb excess carbon dioxide.
How big of a deal is this?
We are seeing our world transformed by climate change and if we do nothing, that transformation will be profound. We call this transformation – the process of climate change and its many effects on our world – “the climate crisis.”
The Earth has experienced cycles of warming and cooling in the past, but experts believe the current warming trend is "proceeding at a rate that is unprecedented in the past 1,300 years."
Join Us and Take Climate Action
On November 20–21, the world will be talking about the climate crisis as part of 24 Hour of Reality: Truth In Action.
For one full day, Climate Reality Leader volunteers trained by former Vice President Al Gore will hold public presentations and conversations on our changing climate in schools, community centers, workplaces, and more across all 50 US states and countries worldwide.
It’s a chance for friends, neighbors, and colleagues to hear the truth of what’s happening to our planet. A chance to learn how we’ll overcome this existential threat together. A chance to turn truth into real action and bold solutions. Now, while we still have time.
There are many ways to get involved, from hosting a free presentation to joining a Truth in Action event in your community. Click here to learn how you can be part of this historic event on November 20–21.
Before You Go
At Climate Reality, we work hard to create high-quality educational content like blogs, e-books, videos, and more to empower people all over the world to fight for climate solutions and stand together to drive the change we need. We are a nonprofit organization that believes there is hope in unity, and that together, we can build a safe, sustainable future.
But we can't do it without your help.
If you enjoyed what you’ve just read and would like to see more, please consider making a generous gift to support our ongoing work to fight climate denial and support solutions.