In January, much of the European Union carbon trading system was shut down in response to the theft of carbon credits from a Czech carbon registry. Blackstone Global Ventures announced: Stolen EUA. Yesterday at 12 CET 475 000 allowances were unlawfully removed from our account with the Czech registry (OTE). We are doing our outmost to resolve the problem and want to make all market participants aware of the incident.
Such crimes can seriously undercut the trustworthiness of carbon credits. National registries in Austria, the Czech Republic, Greece, Estonia and Poland halted all trades while they reviewed their own security. More at New Scientist.
New Scientist also has an excellent article for the general public on the reliability of climate models.