More 60-Second Earth As Charles Darwin knew, earthworms enrich
the soil. But they also increase greenhouse gas emissions.
That's according to a meta-analysis in the journal Nature
Climate Change. [Ingrid M. Lubbers et al, Greenhouse-gas
emissions from soils increased by earthworms] Soil scientists
and biologists reviewed 57 studies to see how earthworms
affected the soil from a climate change perspective. The issue
is substantive: nearly a fifth of global carbon dioxide
emissions come from soil. And earthworms are on the move,
spreading anew through North America for the first time in tens
of thousands of years after being brought over by European
colonists. All that soil digestion in the guts of worms means
more CO2 and more nitrous oxide emanating from the dirt. The
presence of earthworms increased N2O emissions by more than 40
percent. And laughing gas is also a potent greenhouse gas. Worms
also upped soil CO2 emissions, though it remains unclear whether
this is a short-term effect likely to be balanced ou