Short answers, pulled from the story.
Earth's energy budget is the balance between the solar energy the planet absorbs and the longwave radiation it releases back into space. When the two fluxes are equal, the climate is stable; a persistent imbalance drives long-term warming or cooling. Scientists identify monitoring this balance as the single most important metric for understanding climate change.
Of the roughly 340 W/m2 of solar radiation arriving at the top of Earth's atmosphere, about 240 W/m2 is absorbed after roughly 77 W/m2 is reflected by clouds and the atmosphere and 23 W/m2 is reflected by surface albedo. This absorbed solar radiation is called ASR and drives the climate system.
Earth's energy imbalance (EEI) is the difference between the solar energy absorbed and the longwave radiation released to space. During 2005 to 2019 it averaged about 460 terawatts, or 0.90 watts per square meter globally. For the 2012-2024 window it reached 0.99 W/m2, with a 90% confidence interval of 0.70 to 1.28.
Over 90 percent of the excess energy accumulated from ongoing global warming since 1970 has been stored in the ocean. About one-third of that ocean heating has propagated to depths below 700 meters. As of 2020, the rate of ocean heat uptake was approaching 500 TW, equivalent to roughly 14 zettajoules of heat gain in a single year.
The NASA Earth Radiation Budget Experiment used three satellites in the 1980s: the Earth Radiation Budget Satellite (launched October 1984), NOAA-9 (December 1984), and NOAA-10 (September 1986). Since March 2000, NASA's CERES instruments have continued these measurements. CERES data showed EEI rising from about +0.42 W/m2 in 2005 to +1.12 W/m2 in 2019.
In 2012, NASA scientists reported that stopping global warming would require reducing atmospheric CO2 to 350 ppm or below, assuming all other climate forcings remained fixed. By 2020, atmospheric CO2 had reached 415 ppm, and all long-lived greenhouse gases together exceeded a 500 ppm equivalent concentration.