The planet has become measurably darker, absorbing more sunlight and heating up faster as a result. The Earth’s energy imbalance (EEI) has climbed from about 0.5 W/m² in the 2000s to roughly 1.0 W/m² over 2013–2022, confirmed independently by satellite and ocean-heat data.

Most of this is feedback from warming itself, declining reflective clouds and shrinking snow and sea ice, but part of it is a policy accident: the global cleanup of sulfate air pollution has stripped out cooling that was never priced into earlier warming projections. The result: low-sensitivity climate models can no longer reproduce what satellites are measuring, 1.5°C now looks set to be crossed by around 2030, and overshoot is fast becoming the realistic planning assumption for climate-vulnerable states.

This bulletin explains what’s driving the imbalance, what it does and doesn’t mean for the carbon budget, and why solar radiation modification is entering the conversation while the governance to manage it barely exists.