Scientists have used ice cores to monitor atmospheric gases during the cold decade (1810-1819), and the results have been puzzling. The sulfate concentrations found in both Siple Station, Antarctica and central Greenland bounced from 5.0 in January 1816 to 1.1 in August 1818. This means that 25-30 teragrams of sulfur were ejected into the atmosphere, most of which came from Tambora, followed by a rapid decrease through natural processes. Tambora caused the largest shift in sulfur concentrations in ice cores for the past 5,000 years. Estimates of the sulfur yield vary from 10 teragrams (Black et al. 2012) to 120 teragrams (Stothers 2000), with the average of the estimates being 25-30 teragrams. The high concentrations of sulfur could have caused a four-year stratospheric warming of around , resulting in a delayed cooling of surface temperatures that lasted for nine years. (Cole-Dai et al. 2009) This has been dubbed a volcanic winter, similar to a nuclear winter because of the overall decrease in temperatures and abysmal farming conditions.