Hagbard Jonassen (24 May 1903 – 1 March 1977) was a Danish botanist, quaternary geologist, war resister and nuclear disarmament proponent.
Hence, he concluded that 1) cultivated crops such as cereals (except rye), beet, clover and lucerne had very low pollen production and the pollen signal from such areas would have a much higher detection limit than more productive types of land.
2) Pollen dispersal in forest very limited local due to restricted wind speed, which was later confirmed by detailed investigations by Henrik Tauber.
More recent investigations in Denmark and Norway have shown that heathland expansion was metachronous, i.e. occurring at multiple separate locations to different times, suggesting an overriding impact of humans and less of importance for climate change.
[7][8] As a young student and army conscript, he was a co-founder of the Danish branch of War Resisters' International in 1926.