Science Source

Anthropogenic and natural warming inferred from changes in Earth’s energy balance

States that the formal detection of climate warming and its attribution to human influence has so far relied mostly on the difference between spatio-temporal warming patterns of natural and anthropogenic origin
Presents an alternative attribution method that relies on the principle of conservation of energy, without assumptions about spatial warming patterns
Demonstrates that known changes in the global energy balance and in radiative forcing tightly constrain the magnitude of anthropogenic warming
Finds that since the mid-twentieth century, greenhouse gases contributed 0.85 °C of warming (5–95% uncertainty: 0.6–1.1 °C), about half of which was offset by the cooling effects of aerosols, with a total observed change in global temperature of about 0.56 °C
States that the observed trends are extremely unlikely (<5%) to be caused by internal variability, even if current models were found to strongly underestimate it
Concludes that this method is complementary to optimal fingerprinting attribution and produces fully consistent results, thus suggesting an even higher confidence that human-induced causes dominate the observed warming