Microbial Communities to Mitigate Climate Change

2nd Workshop

September 16-18, 2018

“Burning embers” figure showing risk from climate change for five reasons of concern, adapted from Smith et al. 2009.

“Burning embers” figure showing risk from climate change for five reasons of concern, adapted from Smith et al. 2009.

Global climate change has reached the crisis stage.  Former worst-case projections of sea level and temperature rise are now likely scenarios.  Levels of atmospheric carbon dioxide are higher, and accumulating more than fifty time faster, than at any time in the last million years.  Even optimistic carbon emission reduction goals will be insufficient to avert a humanitarian, economic, and ecological catastrophe in as little as 20 years.  In addition to reducing emissions, hundreds of billions of tons of CO2 and other greenhouse gases, primarily methane (CH4) and nitrous oxide (N2O), must be removed from the atmosphere.

Many groups are pursuing materials science or chemical engineering approaches to capture greenhouse gases.  These efforts may prove effective for targeted removal at emission sources, but they are likely to remain too expensive and inefficient to scale to global needs.  Also, carbon capture alone is insufficient without a means of sequestering it so that it does not return to the atmosphere.

Compared to engineering approaches there has been little focus on harnessing the power of microbial communities to mitigate climate change.  However, microbes may offer the best option to remove greenhouse gases from the atmosphere.  The estimated global census of bacteria and archaea exceeds 1030 cells, accounting for most of Earth’s biomass.  These microbes descend from populations that transformed our once sterile planet into a habitable environment.  Today millions of different types of microbes fill the oceans and the atmosphere, orchestrate all the major biogeochemical cycles, and shape the evolution, development, and health of all multicellular life.  They have already evolved the chemistry necessary to process major greenhouse gases, making microbial-based mitigation feasible because it is scalable, highly efficient, and relatively inexpensive.  Consider:

  • Many microbes are capable of trapping carbon by biomineralization, converting CO2 in the atmosphere or ocean into environmentally benign and stable minerals such as calcite and dolomite.
  • Chance of exceeding predicted 2050 temperatures of four models, adapted from Xu andRamanathan 2016 with “Risk of Large Scale Discontinuities” from Smith et al.

    Chance of exceeding predicted 2050 temperatures of four models, adapted from Xu andRamanathan 2016 with “Risk of Large Scale Discontinuities” from Smith et al.

  • Complex microbial communities in coastal habitats and wetlands contain members that can metabolize methane and convert it to larger, more stable biomolecules. As yet uncharacterized microbes in these wetlands can efficiently metabolize even trace amounts of methane from the soil, air, and water.
  • Some microbes can both produce and metabolize N2O, the third most abundant greenhouse gas. Microbial community structure and metabolism can be altered to enhance N2O capture over production.  A recently discovered process in several types of poorly studied microbes metabolizes but does not produce N2O, providing the potential for a true N2O sink.

Converting the potential of microbes into practical solutions for large-scale removal of greenhouse gases from the atmosphere will require creative insights and innovative problem solving from microbiologists, ecologists, oceanographers, geneticists, biochemists, engineers, and others.  The established convening power of the Marine Biological Laboratory attracts the world’s most accomplished scientists to carry out their most far-reaching and creative work, and uniquely positions the lab to address this challenge.