As nations haggle over emission cuts, measurement is tough

Targets ad trust. These are at the heart of a tougher new global climate pact possibly just weeks away.
The bigger the pledged emission 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 emission 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 from burning fossil fuels or deforestation.
Which is why measurement, reporting and auditing of nations’ greenhouse gas emissions is a key focus of marathon UN 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 months.
Rich nations are under pressure from the developing world to sign up to emissions cuts of 25-40% 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 emission growth. China, India, Indonesia and Brazil are among the world’s top carbon polluters.

Huge variability

Rich nations such as Australia and US 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.
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 around 280 ppm at the start of the Industrial Revolution.
If carbon dioxide rises to 450 ppm, the UN climate panel says, the planet is likely to warm by at least 2 degrees Celsius.
Dozens of countries also send greenhouse gas measurement data to the World Meteorological Agency’s World Data Centre for Greenhouse Gases. Such measurements can give annual and seasonal pictures of carbon emissions.
But scientists say we are at least a decade or two away from a monitoring system that can accurately reveal national and regional emissions from fossil fuels or from deforestation and other land use changes.
A global network will also need to take into account the huge amount of carbon dioxide produced and absorbed naturally via so-called sources and sinks.
Trees and oceans soak up carbon dioxide, while bring or rotting vegetation can release it. Winds distribute the gas around the globe, and how this occurs in still not fully understood and is only poorly simulated in complex computer models.

BUILDING A PICTURE

And that is where the real puzzle begins.
Because carbon dioxide is shifted around by the atmosphere, scientists need powerful computers to simulate the movement of air around the globe and to crunch all the data from an army of carbon dioxide monitoring sites on the ground, in the air, and in space.
More accurate measurement and models which, for example, could show how much carbon dioxide is absorbed by forests and oceans, could give in vestors more confidence when putting money into large carbon offset schemes.


incraesing global warming