As nations haggle over CO2 cuts, measurement is tough

By David Fogarty, Climate Change Correspondent, Asia - Analysis

SINGAPORE (Reuters) - Targets and trust. These are at the heart of a tougher new global climate pact possibly just weeks away.

The bigger the pledged emissions cuts or reductions in growth in carbon dioxide pollution, the greater the need to prove nations meet those targets and curb the pace of climate change.

And proof of emissions reductions over time will help unlock billions of dollars in climate funds for poor nations.

The problem, though, is that it is not yet possible to independently monitor a country's greenhouse gas emissions, such as carbon dioxide (CO2) from burning fossil fuels or deforestation.

"Our system is not good enough right now to be able finger one country versus another. I think the density of observations needs to be cranked up two orders of magnitude," said Pieter Tans of the National Oceanic and Atmospheric Administration (NOAA) in Boulder, Colorado.

Rich nations, he said, weren't going to hand over possibly hundreds of billions of dollars to poorer nations to help green their economies purely on trust.

Which is why measurement, reporting and auditing of nations' greenhouse gas emissions is a key focus of marathon U.N. climate talks. The world body hopes the negotiations will lead to agreement on a tougher climate pact from 2013 during a meeting in Copenhagen next month.

Rich nations are under pressure from the developing world to sign up to emissions cuts of 25-40 percent below 1990 levels by 2020 and funnel billions in aid and green technology to the poor.

Big developing nations are also under pressure to curb the pace of their emissions growth. China, India, Indonesia and Brazil are among the world's top carbon polluters.

"If there's no objective system to check lines of success, people are going to claim more than they can deliver. It's natural," said Tans, of NOAA's Earth Systems Research Laboratory.

HUGE VARIABILITY

Rich nations such as Australia and the United States have developed reliable reporting methods on energy use and fossil fuel emissions, said Pep Canadell of the Global Carbon Project. Accuracy for developing countries was often not as good.

"You have huge variability. And of course the issue is let's check on some of the developing countries. That's where it gets the most difficult because the reporting is not that accurate," he said, adding that until recently, China's emissions from burning coal, oil and gas were under-reported by 20 percent.

NOAA runs a global network that tests air samples for a variety of greenhouse gases to build a picture of how their concentrations change over time. Carbon dioxide levels are approaching 390 parts per million (ppm) compared with about 280 ppm at the start of the Industrial Revolution.

If CO2 rises to 450ppm, the U.N. climate panel says the planet is likely to warm by at least two degrees Celsius.