Climate Change Is Already Altering the World’s Gene Pool

A new study finds that a warming world is interfering with genetics, body mass, and the sex ratios of the planet’s wildlife.
(Photo: Hector Amezcua/‘Sacramento Bee’/MCT via Getty Images)
Nov 11, 2016· 2 MIN READ
David Kirby has been a professional journalist for 25 years. His third book, Death at Seaworld, was published in 2012.

The dire impact of human-caused climate change on ecosystems, species, and public health is already well under way, a landmark study published Friday in the journal Science warns.

The study authors analyzed an array of studies showing how climate change is altering the world around us and concluded that the planet’s warming has interfered with more than 80 percent of biological processes, including genetics, body mass, sex ratios, and productivity.

“Climate change has already impacted almost all aspects of life on Earth,” lead author Brett Scheffers, an assistant professor of wildlife ecology and conservation at the University of Florida, wrote in an email.

These changes have occurred after an average global temperature increase of just 1 degree Celsius since preindustrial times. Experts predict that the planet might see 2- to 3-degree-Celsius warming by the end of the century.

It was the first time scientists had analyzed and described all of these changes in their entirety.

“Our paper is unique in that we compiled published case studies showing evidence of climate change responses observed in nature,” Scheffers said. “There are literally thousands of scientific studies on climate change, spanning disciplines from physical to chemical to biological sciences. The power of our research is that it is not a single voice saying climate change is impacting nature but rather a collective voice of research from around the globe, all showing responses to climate change.”

“These processes span from the smallest unit of genetics to the largest biological unit of communities and ecosystems,” Scheffers said.

The authors identified a set of “core ecological processes” (32 in terrestrial and 31 each in marine and freshwater ecosystems) that allow for ecosystem functioning and support services to people.

“Of the 94 processes considered, 82 percent show evidence of impact from climate change,” they wrote.

Many species are experiencing shrinking body size. For example, six species of salamanders in the Appalachian Mountains have lost, on average, 8 percent of their body mass over the past 50 years.

Other physical changes include decreased thermoregulation and altered wing and bill length in birds.

Temperate plants are budding and flowering earlier in spring and later in autumn, the paper said, while fish spawning and the timing of seasonal migrations of animals around the world have also been observed.

“Tropical and boreal species are increasingly incorporated into temperate and polar communities, respectively, and when possible, lowland species are increasingly assimilating into mountain communities,” the researchers wrote.

These radical changes are affecting humans as well as plants and animals.

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“Reduced genetic diversity in crops, inconsistent crop yields, decreased productivity in fisheries from reduced body size, and decreased fruit yields from fewer winter chill events threaten food security,” the study states.

Changes in disease distribution and the emergence of new pathogens and pests are a “direct threat to human health.” Mosquitoes are more efficient at spreading diseases such as chikungunya, dengue, and possibly Zika.

Warmer weather is also altering the genes of many species.

“Between the 1960s and 2000s the water flea evolved to cope with higher thermal extremes in the U.K., and cornflower life history traits have recently evolved in response to warmer springs across northern France,” the paper said. Pink salmon, meanwhile, are migrating earlier, “with decreased frequency of incidence of a genetic marker that encodes for late migration.”

There is also evidence that global warming has affected sex ratios in some species and has been implicated in the masculinization of lizards and the feminization of turtles.

Some species have benefited, while others have not. Among marine life, 52 percent of warm-adapted species increased in abundance, while an equal ratio of cold-adapted species decreased, Scheffers said.

“Warm-loving species are benefiting from warming in the oceans and on land,” he said. “But this is not a sign that everything is OK. Many of the ecosystems where this is occurring have completely failed. We are seeing wholesale losses in ecosystems and in some situations.”

Shaye Wolf, climate science director at the Center for Biological Diversity, praised the study, saying, “The scale of the impact is staggering. This is a very important contribution to the science and the very serious consequences for nature and people.”

The need for “strong and rapid climate action” is urgent, Wolf said. “If we keep going in this direction, we are going to lose priceless things that we cannot get back,” she said. “We are disrupting the very fabric of life, and we need to rapidly change course.”

Scheffers agreed but said the political climate in the United States is not conducive to the changes needed.

“What’s important is that we make these decisions rationally and logically rather than relying on wishful thinking and a belief system steeped in nonscientific ideology,” he said. “I do think our future President Trump can seriously threaten America’s involvement in the Paris Agreement and America’s role as a global leader.”