He is the former president and CEO of The Heartland Institute, an American nonprofit conservative and libertarian public policy think tank based in Arlington Heights, Illinois.

[3] In 1984, David Padden founded the Heartland Institute — an American conservative and libertarian public policy think tank — and put Bast in charge of the nascent organization.

[5] In 2014, he co-authored an article entitled "The Myth of the Climate Change '97%'" in the Wall Street Journal along with Roy Spencer which argued that the oft-cited claim that "97% of the world's scientists believe climate change is an urgent problem" is misleading because the figure is derived from surveys with small sample sizes, and the questionnaire conflates belief in negligible global warming with belief in dangerous global warming.

[10] Bast told Bloomberg News that the Heartland Institute does not deny climate change, but they are skeptical of the scientific consensus that man-made global warming is a significant danger to the planet.

[11] According to Nature, Bast does not necessarily deny that humans are having an influence on the climate, but he does question the forecasts of catastrophic impacts and the rationale for curbing carbon emissions.