Unfortunately, what you don’t know can in fact hurt you. Scientist don’t fully understand the feedback loops in our climate, but scientists know they’re real and dangerous. A few extra degrees of heat could cause irreversible changes to the earth.(1)
What are feedback loops? They’re vicious cycles, snowball effects. A snowball starts rolling down a hill, picks up snow, and so rolls faster, picking up even more snow. Vicious cycles like this can also happen in our oceans and air. Most unhelpfully accelerate warming, but there is one that could be helpful.
How could a warming climate create vicious cycles? Here are four ways:
1. Arctic ice melts and stops reflecting the sun
- On average, NASA found that enough sea ice to cover 40 New York Cities disappeared every year from 1996 to 2013.
- Ice helps keep Earth cool by reflecting most of the sunlight that hits it. When it melts, the water below absorbs more sunlight, and more ice melts.
2. Warm oceans lead to even warmer oceans
- Oceans absorb a quarter of all the carbon dioxide released by people.
Warmer oceans absorb less carbon dioxide than cooler oceans.
- That unabsorbed carbon will stay in the air and trap more heat on earth, further warming oceans and the Earth.
3. Frozen soil thaws and releases greenhouse gases
- Permafrost is frozen soil that has carbon trapped in it.
Carbon escaped from melting permafrost would cause more heating and more permafrost melt.
- If all the permafrost melts, it could release 1,400 billion metric tons amounts of heat-trapping gases into the air. This is more than all the carbon in the air today.
4. More clouds reflect more sunlight
Clouds can cause both warming and cooling. They block out light coming from the sun. But they also trap heat leaving the Earth. Scientists are actively researching which effect will have the bigger influence in the future.
- Clouds are one feedback loop that may cool the Earth.
- Warming increases evaporation which means more clouds
- Clouds have a mixed effect. They reflect sunlight back into space which cools the Earth, but they can also trap heat.
- The science is unsettled on whether they will cause more warming or cooling.
The scary thing about feedback loops is that scientists don’t know how close they are to cycling out of control. If they did, the climate could heat up on its own momentum. Right now people are driving climate change, which mean we can also stop it. Feedback loops could take the ability to stop climate change out of human hands. This is unlikely to happen anytime soon, but it demands our attention because the consequences would be catastrophic.
Feedback loops are one reason a few degrees of climate change could be dangerous. We don’t know what temperatures will trigger these cycles, or how long we can wait and still be safe. But when standing on thin ice, the conservative approach is to walk carefully, and head to sturdy ground.
Understanding feedback loops in 30 seconds
- Climate scientists worry that climate change could lead to create self-perpetuating warming cycles
- The thresholds for setting off most feedback loops, such as polar ice melt, are not well understood.
- Not all feedback loops warm the Earth. Increased cloud creation may cause cooling.