Earth’s climate is warming because of human activities such as burning fossil fuels. To predict the consequences of these activities, climate scientists make theoretical mathematical models of Earth’s climate system. To work, these models need to capture a complicated web of interactions, including processes going on in the atmosphere, the oceans, polar glaciers, and land, that all act together to produce the climate. Many of these processes involve feedback loops whereby the process sets in play other processes that either amplify or dampen the initial change.
Positive feedbacks—those that amplify the initial change—are particularly concerning as we continue to heat the planet through our actions. This happens when an effect loops back on its cause to make the causing process larger or more intense. For example, when arctic ice melts, it exposes sea water. Sea water absorbs more solar radiation than ice does. Because Earth absorbs more solar radiation, the planet warms more, and more ice melts, and on it goes in a vicious circle. If scientists don’t recognize and understand amplifying feedback loops, they could underestimate how bad the effects of climate change will be.
In 2023 an international team of scientists published their analysis of feedback loops in the climate system. They found twenty-seven different, potentially troubling amplifying feedback loops in Earth’s climate system. Some of these might be associated with tipping points that could trigger big permanent changes. The scientists called for more research to understand the complex processes their findings highlight. They also think efforts to curb fossil fuel burning and other climate changing activities need to be speeded up, to avoid the possible consequences of the feedback loops they found.