by John Anthony, Energy and Climate Communications Director, UN Foundation, writing from the UN climate summit in Poznan, Poland

One thing that is not talked about enough at the UN climate negotiations is just how fundamentally complex a transition the world is attempting to make with regard to reducing carbon dioxide emissions.

There's plenty of finger pointing: China and India this, and Brazil that. And too often, the United States this and that.

China and India rightly point to the industrialized world's "historical" or sheer volume of emissions since the early 20th century. They are both in periods of rapid industrialization which, though greatly polluting their air and water, and recently, in China's case, surpassing the level of the U.S. emissions, are also achieving vast improvements in quality of life for millions upon millions of their people.

Another point of great contention is "per capita emissions." China is now emitting more than the U.S., but they also have more than four times the population. So the two nations are comparable when it comes to how much carbon they put in the atmosphere, but not even close when it comes to "carbon intensity."

And that is one new area which holds promise as a component to a potential deal - agreeing to commit to energy efficiency gains, which are largely attainable with existing technologies.But from the Chinese and Indian perspective, asking them to commit to change over to cleaner and more expensive sources of energy is akin to asking them to constrain their growth, and the human and social improvements which come with it.

The planet doesn't recognize where emissions come from, of course, and science is telling us that we have limited time in which to act to prevent the most catastrophic effects of climate change. But an indigenous group in Brazil or Papua New Guinea isn't likely to be steeped in the findings of the IPCC.

They do recognize that their governments are considering provisions of a climate deal which would set aside wide swaths of forested land, where they have long lived, and farmed, felling trees in the process, in order to serve as invaluable carbon "sinks" - or sponges for absorbing carbon dioxide.

And herein lies a crucial crux of the negotiations: trust, and a lack of it. Do indigenous people trust that they will be compensated for restrictions on their land use? Do developing nations trust that the industrialized world will provide them with access to cleaner burning technologies?

A comprehensive agreement on emissions reductions and timetables by which to achieve them is the goal for Copenhagen. But all the heavy lifting must not be left to next year. Trust can be engendered by areas of agreement forged along the road there. There yet remains hope the talks here in Poland can achieve that.