The 33C «discrepancy» is based on a «current» estimate of the upper atmosphere radiant «equilibrium» value of about 240 Wm - 2 equating to an ideal S - B equivalent temperature of -18 C degree and a SWAG estimate of the «average» «surface» temperature of 15C which would have an ideal S - B equivalent energy of about 390 Wm - 2. (judithcurry.com)
Finally, an application example is given using the series of the CO2 annual emissions intensity in Greece (kg per kg of oil equivalent energy use) for the period 1961 - 2010. (mpra.ub.uni-muenchen.de)
The more recent researchers state that «the earliest plants and animals had simple and quite different bodies, but natural selection has acted on the two groups so the geometries of modern trees and animals are, remarkably, displaying equivalent energy efficiencies. (faith.org.uk)