A climate feedback is a process that can either amplify or slow down the effects of climate change. 

A feedback that increases an initial warming is called a "Positive Feedback" while a feedback that tends to cool down the increasing temperatures is a "Negative Feedback."

It’s like a domino effect: once one domino falls, it starts a cyclical chain reaction, where all the elements are strictly connected.

In the past years scientists have identified several Positive Feedback Loops in the climate system.

One, for example, is caused by greenhouse gases (GHGs) like carbon dioxide and methane, generated by burning fossil fuels. These gases absorb and store the sun's heat in the atmosphere. The more GHGs in the air, the more the heat that will warm up the planet, disrupting the delicate balance of the climate system.

Another Positive Feedback can be found observing the water cycle.

When greenhouse gases are emitted, the atmosphere warms up. Warmer air makes more water evaporate empting oceans, lakes and rivers and entering the atmosphere.

Hot air holds more vapor, and vapor traps even more heat, making the initial warming worse. More heat means more water evaporating and so on...

It’s a vicious cycle: climate change causes a cascade of effects that result in even more climate change. Without the regulating action of Negative Feedback Loops, a Positive Loop can eventually spiral out of control, creating permanent changes in the climate system. This point of no return is called a “Tipping Point”. 

Another example of a Positive Feedback Loop is what’s happening in the Arctic, where methane and carbon can be found in the peat bogs trapped in the permafrost as well as in the seafloor. When the permafrost thaws, thanks to climate change, the methane and carbon are released into the atmosphere adding more GHGs to the equation, which will ultimately lead to more global warming, more heat, more ice melting and more GHGs… well, you get our point.

Another Feedback Loop in the Arctic with global implications? The reduction in sea ice coverage, particularly in the summertime.

The Arctic Ocean plays a very important role in keeping the Earth cool: the ice on its surface creates a wide white surface, able to reflect sun rays. 

Unfortunately, the sea-ice cover in the Arctic is shrinking, and this contributes to accelerate global warming and climate change, resulting in even more ice loss.

This is happening because the lack of ice is uncovering the much darker surface of the ocean: the dark water absorbs the sun’s radiation instead of reflecting it causing, needles to say, more heat and more vapor.

Elsewhere, hotter temperatures create the perfect conditions for wildfires that release GHGs and shrink the forests that absorb CO2 from the atmosphere, ultimately leading to even hotter temperatures and, guess what, even more wildfires.

Sadly, there are too many examples of Positive Feedback Loops but good news is there are also good forces on this planet: Negative Feedback Loops are processes that are able to slow down the tragic effects of Positive Feedbacks, helping stabilize the system.

There are several climate changes that can result in Negative Feedbacks.

As we said, even though the heat is increasing, there are still some changes in our climate that are leading us toward cooler temperatures.

For example, as the surface temperature of the Earth goes up, there are increased levels of evaporation from the oceans. This evaporation results in more clouds forming in the lower atmosphere. These clouds, in turn, reflect some solar radiations back into space, slightly decreasing the surface temperature.

Another negative feedback occurs, weirdly enough, thanks to the increasing temperatures of the Earth: as the Stefan-Boltzmann law states, the warmer the planet the more infrared radiation is emitted back into space.

 When the amount of outgoing radiation increases, it causes a cooling effect.

Why do we need to know about climate feedback loops and talk about them? 

Feedback Loops are affecting the climate crisis in ways that are still largely unknown.

More research and awareness are fundamental in order to give these phenomena the consideration they deserve: for example, they were not taken into account in the Paris Agreement, when setting the goal to limit global warming below 2 degrees Celsius.

Lowering emissions by transitioning to renewable energy, planting trees, ending deforestation and adopting sustainable agricultural techniques, can help reduce the  greenhouse gas emissions. These and many other actions can lower the planet’s temperature, reduce excess carbon in the atmosphere and help Negative Feedback Loops (the good ones) mitigate the effects of global warming.