Marcel Crok is the co-founder of the Climate Intelligence Foundation, CLINTEL. Born in 1971, Crok studied chemistry in Amsterdam and Leiden. In 1997, he became a freelance science journalist after an internship at Chemisch Weekblad (now C2W). In 2001, he became an editor at the technology magazine De Ingenieur and, from 2003, at the monthly magazine Natuurwetenschap & Techniek (NWT).

In February 2005, Crok published a major and critical  article in NWT about the hockey stick graph ( English version ). This article provoked a significant response, and he has been closely following the climate debate ever since. Later that year, the hockey stick story earned him the first  Glass Griffin , an incentive prize for young science journalists.

In 2019, Crok, together with emeritus professor Guus Berkhout of Delft University of Technology, founded the Climate Intelligence Foundation (CLINTEL). CLINTEL operates as a think tank and watchdog in the areas of climate change and climate policy. CLINTEL operates globally, including through the World Climate Declaration , which has been signed by more than 800 scientists and experts. In 2023, Crok, along with American Andy May and a group of researchers from the Clintel network, published the book " The Frozen Climate Views of the IPCC ." In the book, they critique the sixth IPCC report.