Microbes hold the balance in climate crisis

Scientists search for cyanobacteria on Lake Chur-kul in Kyrgyzstan. Image: By Jan Kwiatowski, via Wikimedia Commons

You need powerful microscopes to see microbes. Few microbiologists claim to know much about most of them. But they are vital in the climate crisis.

LONDON, 28 June, 2019 − Thirty scientists from nine nations have issued a challenge to the rest of climate science: don’t forget the microbes.

They argue that research is ignoring the silent, unseen majority that makes up the microbial world. Lifeforms that add up to a huge proportion of living matter on the planet are being largely left out of climate calculations.

Microbes have been around for 3.8 billion years, manipulating sunlight and turning carbon dioxide into carbon-based living tissue, and the mass of all the microbes on the planet probably contains 70 billion tonnes of carbon alone.

They are biodiversity’s bottom line. They are the arbiters of the planet’s resources. They were the first living things on the planet, and will almost certainly be the last survivors.

They are the only living things at vast depths and colossal pressures. Far below the planetary surface, many survive at temperatures beyond boiling point, in lakes composed of alkali, and some can even digest radioactive material.

“The impact of climate change will depend heavily on the responses of micro-organisms, which are essential for achieving an environmentally sustainable future”

They affect the chemistry of the atmosphere, they colonise the intestines of ruminant species to release enormous volumes of the potent greenhouse gas methane, they bury carbon at depth and they decompose vegetation to release new atmospheric carbon dioxide.

They support all life, and powerfully affect life’s health. They affect climate change, and in turn they are affected by climate change.

“Micro-organisms, which include bacteria and viruses, are lifeforms that you don’t see on conservation websites”, said Ricardo Cavicchioli, of the University of New South Wales in Sydney, Australia.

“They support the existence of all higher lifeforms and are critically important in regulating climate change. However they are rarely the focus of climate change studies and policy developments.”

Professor Cavicchioli and colleagues from Germany, the US, Norway, the UK, Switzerland, Italy, the Netherlands and Canada issue what they call their “consensus statement” in the journal Nature Reviews Microbiology.

Globally important

It is not as if climate researchers are unaware of the microbial connection: there is evidence of the powerful role microscopic life plays in ocean warming and on land.

But the consensus statement says it “documents the central role and global importance of micro-organisms in climate change biology. It also puts humanity on notice that the impact of climate change will depend heavily on the responses of micro-organisms, which are essential for achieving an environmentally sustainable future.”

The scientists want to see more research, closer attention to the microbial underpinning of climate change, and more education. They point out that 90% of the mass of living things in the ocean is microbial. Marine phytoplankton take light energy from the sun, remove carbon dioxide from the atmosphere and provide the basis of the ocean’s life support system. A warming world could mean a diminished ocean food web.

On land, microbes are powerful agencies in both agriculture and disease. “Farming ruminant animals releases vast quantities of methane from the microbes living in their rumen – so decisions about global farming practices need to consider these consequences,” said Professor Cavicchioli.

“And lastly, climate change worsens the impact of pathogenic microbes on animals (including humans) − that’s because climate change is stressing native life, making it easier for pathogens to cause disease.” − Climate News Network