By Pierre L. Gosselin
A new study (Hanna et al., 2021) affirms a significant warming trend occurred in the late 20th century across Greenland, mirroring the warming that occurred in the early 20th century. Since 2001, the temperature trends across Greenland have stopped rising and begun cooling.
A temperature pattern has been emerging in Greenland during the last few decades that does not align with alarming proclamations of catastrophic ice sheet melt from accelerated warming.
After significant summer (winter) warming of about 2°C (to 4°C) from the 1980s to 2000, Greenland’s warming trend has plateaued and, since 2012, a cooling trend has commenced.
“[S]ince 2001 overall temperature trends are generally flat and insignificant due to a cooling pattern over the last 6–7 years.”
“According to MAR, and in line with the DMI coastal station analysis above, much of southern and southwest Greenland has not warmed during autumn since 1991. MAR trends between 2001 and 2019 show the southwest of the country cooling in winter and spring, and deeper, much more widespread cooling in west Greenland in autumn.”
Image Source: Hanna et al., 2021
Greenland’s Climate History Recycled
The temperature trends across Greenland seem to have followed an oscillatory pattern over the last 100 years. Between 1920 and 1930, Greenland abruptly warmed “between 2 and 4°C in less than ten years,” with some stations recording as much as 6°C warming during this span (Chylek et al., 2004).
Interestingly, Greenland’s “annual whole ice sheet 1919–32 warming trend [was] 33% greater in magnitude than the 1994–2007 warming” (Box et al., 2009).
Greenland temperatures plateaued during the 1930s and then, after 1940, a 50-year-long cooling trend commenced (Chylek et al., 2004).
Image Source: Chylek et al., 2004
Dubious CO2-Induced Greenland Warming
For some reason, Hanna and colleagues believe it is reasonable to assume CO2 has been driving the recent (1981-2000) warming even though they acknowledge CO2 has continued rising even as temperatures have flattened and cooled this century. They oddly project dramatic warming and ice sheet melt for the coming decades based on CO2 emissions scenarios.
Apparently these scientists are unaware of the measurements indicating the CO2 greenhouse effect forcing is as “comparatively weak” for Greenland as it is for Antarctica (-2.9 W/m² to +1 W/m²) according to Schmithusen et al. (2015), effectively ruling out a significant or even causal role for CO2 forcing of Greenland’s climate trends.