Low-cloud climate feedback

A sheet of low cloud over the ocean reflects sunlight back toward space. As the ocean warms, will such clouds cover more or less of it, and will their changing reflection amplify or offset the warming?[1] [2]

Low clouds over the ocean reflect sunlight away from Earth. Under sustained warming, how will their cover change, and how much will that change reinforce or offset the initial warming?

Consider two warming patterns with the same overall temperature rise, but extra warming concentrated in different ocean regions. In a 2026 framework, relatively warmer regions tend to lose low cloud, so shifting the warming pattern changes where reflective cover is lost. Loss of reflection adds a positive feedback; increased reflection gives a negative feedback. These signs describe the energy response, not whether the weather is desirable.[1] [2]

A satellite reconstruction finds increased tropical low-cloud cover over its historical period. Future warming can have a different ocean-temperature pattern, so that past response does not establish the future sign.[1] [2]

A separate 2026 satellite reconstruction infers a negative low-cloud feedback for its historical warming pattern, while climate-model projections under idealized future carbon-dioxide forcing give a positive feedback. The historical sign is not an established future sign. Remaining uncertainty includes the future ocean-temperature pattern and the clouds’ response to it.[1] [2]

That response affects estimates of how much Earth warms.[1] [2]

Cloud reflection can reinforce warming or partly counteract it. Its response changes the warming inferred from the same greenhouse forcing. Connecting regional ocean changes to cloud changes therefore matters for global projections, while a successful description of historical clouds must still be tested under future patterns.[1] [2]