Greta Thunberg lives in Sweden. According to peer-reviewed science, Sweden was at least 3°C warmer than it is today about 6000 to 9000 years ago, when CO2 concentrations lingered around 265 ppm. At 410 ppm CO2, 21st century Sweden is colder now than almost any time in the last 9000 years.
Image Source: Grudd, 2008
A Much Warmer Northern Hemisphere
During the Medieval Warm Period, wine vineyards flourished in Scandinavia and Russia at the same latitude (55°N) where polar bears roam today.
Image Source: Lamb, 1959
Earlier in the Holocene, when CO2 levels hovered around 260 ppm, vast forests extended all the way up to the coasts of the Arctic Ocean (Russia), suggesting temperatures were up to 7°C warmer than today (MacDonald et al., 2000).
Image Source: MacDonald et al., 2000
The limits of Arctic sea ice (north of Greenland) extended 1000 kilometers further north of where sea ice extends to today (2007), as Arctic Ocean temperatures were 2-4°C warmer about 8500 to 6000 years ago (Funder et al., 2011).
Image Source: Funder et al., 2011
Throughout the Northern Hemisphere (Austria, Canada, Iceland, Russia), summer air temperatures were about 3° to 5°C warmer than today between 10,000 and 8000 years ago, when CO2 values held steady at 260 ppm (Ilyashuk et al., 2011).
Image Source: Ilyashuk et al., 2011
Greta Thunberg’s Sweden: Colder As CO2 Rises
Sweden’s CO2 mitigation advocate Greta Thunberg. Image Source: Greta’s Twitter site
Greta Thunberg has been warning the world about the dangerous warming consequences of the modern rise in CO2 concentrations.
And yet despite CO2 levels rising from 260 ppm to 410 ppm since the Early Holocene, the country where she resides has continued to record nearly the coldest temperatures of the last 9000 years.
For example, permafrost that exists today in northern Sweden wasn’t present just a few hundred years ago, as the region was too warm to support permafrost until recent centuries (Sannel et al., 2018).
Image Source: Sannel et al., 2018
Tree trunk remains located 600 to 700 meters atop the limits of today’s barren mountain treelines (northern Sweden) date to the Early Holocene, suggesting (with the lapse rate) temperatures were 3-4°C warmer than today from about 9000 to 6000 years ago (Kullman, 2018).
Image Source: Kullman, 2018
There are many proxy reconstructions that show modern Sweden’s temperatures are either the coldest or nearly the coldest of the last 9000 years. They also suggest most of the Holocene was 3°C to 4°C warmer than today for this region (Antonsson and Seppä, 2007, Bigler e tal., 2002, Bigler et al., 2006, Borzenkova et al., 2015, Grudd, 2008).
Image Source: Antonsson and Seppä, 2007
Image Source: Bigler e tal., 2002
Image Source: Bigler et al., 2006
Image Source: Borzenkova et al., 2015
Image Source: Grudd, 2008
Does Greta Know?
These scientific conclusions affirming a much warmer Northern Hemisphere and Sweden do not support the poplularized position that climate change is a manifest consequence of a dangerous rise in CO2 emissions.
Greta Thunberg likely hasn’t been made aware of this science; it undermines the narrative the adults around her have been pushing.