The Global Ice Issue
If the moon and Earth are the same distance from the sun, why does the moon not have plants and can have an average surface temperature of -143 degrees Celsius.
Our beautiful, freezing, and lifeless moon. Source: Pexels
The key difference? Earth has a big blanket of gas around it called an atmosphere that keeps the heat in while the moon does not.
The sun is the main heat source for both Earth and the moon. The sun warms us through infrared radiation (IR). However, once the radiation has hit Earth and tries to bounce away, gases called greenhouse gases trap the radiation and bounce it back to Earth in a game of radiation Ping-Pong. This group of gases are called greenhouse gases because they are shrouded all around the Earth and keep us warm, just as a greenhouse keeps plants warm. They retain the heat that has hit the Earth’s surface.
Despite the hard time everyone gives greenhouse gases, without them in the atmosphere Earth would become hopeless at sustaining life as we know it.
Even though a very small amount of gases in our atmosphere are greenhouse gases, they do their job extremely well.
While Greenhouse gases trap the heat that has bounced off Earth into the atmosphere, something else plays a role in warming and cooling our planet.
Ice is one of the most reflective natural substances the Earth’s surface has to offer. So it plays a crucial role in making sure the Earth reflects the IR from the sun, keeping us cool.
Ice has an albedo of 0.9, which means it reflects 90% of the solar energy that it comes into contact with. Meanwhile the open ocean has an albedo of 0.06, which means it reflects only 6% of the solar radiation that hits it and absorbs a whopping 94%.
So you can probably tell why melting ice caps are a bad thing, huh?
Ice reflects solar radiation that prevents the Earth from warming. This makes it easier for more ice to form, which further prevents the absorption of IR radiation.
More ice = more reflection = more cooling = more ice.
This set of processes is known as a positive feedback loop. They encourage one another in a never-ending cycle.
But, this process can also occur in reverse. As ice melts, there is less ice to reflect IR and more ocean surface to absorb it.
But wait! There’s more.
All that albedo, melting away. Source: Pexels
As ice melts, methane (the gas also made from cow farts) and water vapour are released into the atmosphere. Methane and water vapour are greenhouse gases that make sensational Earth blankets, and their release makes it harder for the radiation to leave the atmosphere, and makes it more likely they are sent back flying back toward Earth.
With the ice melting and the atmosphere thickening, the Earth is absorbing IR at a rate never experienced before.
We are burning the candle at both ends here. We are losing ice, absorbing more solar radiation and thickening our atmosphere. It’s like we’ve wrapped ourselves in an electric blanket and turned the heater on. The only issue is, we can take a blanket off, but we can’t re-freeze the ice caps. Once they go, they’re gone forever.
So! These are the take home messages, the points to write home about:
- Ice is good; we need it so we don’t fry.
- Greenhouse gases are good in moderation. They keep us from feeling like we’re on the moon.