The global carbon market is fast expanding. More than 8 gigatonnes of CO2-equivalent changed hands last year, up nearly 70% on the previous year’s volume, according to a report released today by Point Carbon.

The value of carbon trading, however, was little changed; €94bn in 2009 versus €92bn in 2008. The weighted-average price of an emissions-reduction credit in the European Union, by far the world’s largest carbon trading venue, fell by more than 40% in 2009.

Futures predict gradually rising prices in the years ahead but exchanges will be more concerned with volumes. Recent history should give them reason to be optimistic.