When the Iowa state board of education voted to adopt a revised set of state science standards on May 8, 2025, language about evolution and climate change that was censored from a previous draft remained absent.
In a previous revision of the standards, the word "evolution" was scrubbed, although not completely, from the current standards: for example, "Biological Evolution" became "Biological Change Over Time," "evolutionary relationships" became "relationships," and "simultaneous coevolution" became "simultaneous change." A reference to the 4.6-billion-year age of the earth was removed. Similarly, "climate change" became "climate trends," while references to impacts of human activity on the environment became references to impacts on the environment.
Subsequently, NCSE Deputy Director Glenn Branch, writing on Bleeding Heartland (February 12, 2025), urged Iowa to retain "the scientifically accurate and pedagogically appropriate language about evolution and climate change" in its current state science standards. Similarly, the Des Moines Register (March 9, 2025) commended the Iowans who protested these changes, commenting, "It's alarming that somebody with influence thought that muddying these waters was worth considering."
In the adopted revision of the standards, although "Biological Evolution" and "simultaneous coevolution" were restored, "evolutionary relationships" was not, and the reference to the 4.6-billion-year age of the earth is still absent. The reference to "climate change" is now to "climate changes and trends," but "the rise in global temperatures over the past century" is still the vaguer "the change in global temperatures in time" and the phrase "due to human activity," removed from a discussion of relationships among Earth systems, is still absent.
After the board's vote, KCRG in Cedar Rapids (May 8, 2025) summarized, "Teachers across the state will soon have more vague teaching standards for topics like climate change and evolution." NCSE's Branch explained that the new standards obscure human responsibility for climate change, adding, "If Iowa students don't come to understand this today, they won't be in position to take suitable action tomorrow." KCRG also observed that the changes to the standards still have not been explained.
"These changes detract from the scientific integrity of the standards," NCSE Executive Director Amanda Townley commented. "Fortunately, Iowa's science teachers still have the power to continue teaching about climate change and evolution forthrightly."
