Emissions of nitrous oxide could double by the
middle of the century if left unchecked, a new study finds. And
nitrous oxide is the third biggest contributor to manmade climate
warming. So should we be worried?
Most people know nitrous oxide as 'laughing gas', used as a mild
anaesthetic by doctors and dentists. But it is also a powerful
Nitrous oxide is the third-largest contributor
to the manmade greenhouse effect, after carbon dioxide and
A new study, published in the journal Environmental
Research Letters, brings together all the
projections for future nitrous oxide emissions from different
researchers. The results show that on average emissions will
increase 83 per cent by 2050, if we carry on with business as
The study also looks at how emissions might be
curbed between now and the middle of the century. If 'moderate'
attempts are made, the study finds, nitrous oxides would still
increase by around 26 per cent. But emissions could reduce by as
much as 22 per cent if we really get our act together.
All the projections were made using a starting point
of 2005. This means the researchers are able to see how actual
nitrous oxide emissions in recent years compare to the different
scenarios. And the bad news is that we're currently on the
business-as-usual path, the researchers say.
Bacteria release nitrous oxide
naturally by breaking down nitrogen in the soil
and oceans. Total emissions from natural sources are currently
around twice those of emissions from human activities.
But while natural emissions have not
changed significantly since the industrial revolution, manmade
emissions have. This increase has caused nitrous oxide
concentrations in the atmosphere to rise steadily since the the
mid-19th century, as shown below.