A few weeks back I reported on a talk by Labour MP Colin Challen at which he asked whether any country would really be willing to impose tough sanctions on the US in the event of it breaching any Copenhagen climate change deal.
It is arguably the singular most important question surrounding the entire Copenhagen process and will determine whether we end up with a real deal that promises to deliver deep cuts in carbon emissions or a symbolic gesture that paves the way for another two decades of diplomatic squabbles. And yet, up to now the issue of enforcement has been pushed so far to the sidelines of the UN negotiating process that it resembles little more than an inconvenient dot on the horizon.
Consequently, it was hugely encouraging to read this morning that the UK government has commissioned a study on precisely this issue.
It may be about 18 months too late given the glacial pace at which the UN negotiations appear to be moving, but it appears to clearly address the issue of what to do when a country breaches the emission targets that are expected to be agreed under Copenhagen. And even more significantly, it is unapologetic about the need for strong international carbon watchdogs and enforcement agencies to enforce the deal.
The report, An Institutional Architecture for Climate Change, recommends that the UN set up a new carbon watchdog similar to the International Atomic Energy Agency and imbue it with the power to carry out snap inspections and impose harsh penalties on those nations that breach the terms of any climate deal.
This might seem like little more than diplomatic house-keeping, but the reports' authors, Alex Evans and David Steven of the Centre on International Co-operation at New York University, are fully aware that what they are calling for has massive implications.
"Either countries play a full part in the system, or they sit outside the international system and are effectively barred from all forms of international co-operation," they say. "Carbon default, in other words, would become as weighty an issue as sovereign default, or failure to comply with a security council resolution. That this should currently seem inconceivable indicates the extent of the shift in understanding that is still needed."
You did read that right - breaching carbon targets should be on a par with "failure to comply with a security council resolution". Miss your targets and you join North Korea and Iran as the focus of the world's condemnation.
What that means in practice is that any country that consistently misses carbon targets or reneges on the deal should face pariah status and all the crippling economic sanctions that go with that.
It is an idea that sounds entirely right and proper in principle, but takes on a different hue when you consider the next US president could conceivably be the climate change doubting Sarah Palin, or that Putin's Russia has been one of the most vocal critics of the current negotiating process.
Ultimately however it is this issue of enforcement that will be the real test of political and business leaders' commitment to tackling climate change.
A nice and cosy deal at Copenhagen that sets out aspirational emission targets might well look good, and will certainly prove enough for politicians to claim success. But without an internationally feared watchdog we are doomed to repeat the mistakes that made the Kyoto Treaty such a failure.
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