Regarding climate change, biologists warn: Don’t forget the microbes

Much of the damage from climate change is in front of our eyes: Bleached-out coral reefs, destroyed homes and flooded neighborhoods ravaged by hurricanes, dangerous wildfires scorching Northern California forests. Worst-case scenarios involve remade coastlines, stunted crops, and social unrest caused by scarce resources.

An international group of microbiologists, however, is warning that as science tries to search for solutions to climate change, it’s ignoring the potential consequences for climate change’s tiniest, unseen victims – the world’s microbial communities.

Frank Stewart, associate professor in the School of Biological Sciences, is one of more than 30 microbiologists from nine countries who today issued a statement urging scientists to conduct more research on microbes and how they are affected by climate change.

The statement, “Scientist’s warning to humanity: Micro-organisms and climate change,” was published in the journal Nature Reviews Microbiology. Lead author is Rick Cavicchioli, microbiologist at the School of Biotechnology and Biomolecular Sciences, in the University of New South Wales (Sydney).

“The consensus statement by Cavicchiolli and colleagues is an overdue warning bell,” Stewart says. “Its goal is to alert stakeholders that major consequences of climate change are fundamentally microbial in nature. As a co-author, I'm hopeful this statement finds a wide audience of nonscientists and scientists alike and also serves as a call to action. Microbes must be considered in solving the problem of climate change.”

The impact on microbes

In the statement, Cavicchiolli calls microbes the “unseen majority” of all life on Earth. Their communities serve as the biosphere’s support system, playing key roles in everything from animal and human health, to agriculture and food production.

A cited example: An estimated 90% of the ocean’s biomass consists of microbes. That includes phytoplankton, lifeforms that are not only at the start of the marine food chain, but also do their part to remove carbon dioxide from the atmosphere. But the abundance of some phytoplankton species is tied to sea ice. The continued loss of ice as oceans warm could therefore harm the ocean food web.

“Climate change is literally starving ocean life,” Cavicchioli said in a press release about the consensus statement.

The microbiologists are also worried about microbial environments on land. Microbes release important greenhouse gases like methane and nitrous oxide, but climate change can boost those emissions to unhealthy levels. It can also make it easier for pathogenic microbes to cause diseases in humans, animals, and plants. Climate change affects the range of flying insects that carry some of those pathogens. “The end result is the increased spread of disease, and serious threats to global food supplies,” Cavicchioli said.

“Just as microbes in our bodies critically affect our health, microbes in the environment critically affect the health of ecosystems,” Stewart says. “But microbial processes are changing dramatically under global climate change, including in ways that fundamentally alter food webs and accelerate climate change.”

A call to boost research

Georgia Tech researchers such as Stewart, Mark Hay, Kim Cobb, and Joel Kostka have become experts in researching climate change’s impact on diverse ecosystems, from coral reefs to subarctic peat bogs. Much of their work already focuses on microbes and the roles they play in these stressed environments.

“For example, ocean warming is driving the loss of oxygen from seawater, leading to large swaths of ocean dominated exclusively by microbes,” Stewart says. “Our research at Georgia Tech tries to understand how such changes affect the microbial cycling of essential nutrients.”

According to the consensus paper, that kind of research should play a bigger role when governments and scientists work on policy and management decisions that might mitigate climate change. Also, research that ties biology to worldwide geophysical and climate processes should give greater consideration of microbial processes.

“This goes to the heart of climate change,” Cavicchioli says. “If microorganisms aren’t considered effectively, it means models cannot be generated properly and predictions could be inaccurate.”

Microbiologists can endorse the consensus statement and add their names to it here: https://www.babs.unsw.edu.au/research/microbiologists-warning-humanity