GLASGOW, Scotland — The U.N. climate summit in Glasgow is scheduled to wrap up on Friday.

Negotiators have released a draft agreement that calls on countries to speed up cuts in carbon emissions. Wealthy countries have historically contributed the most greenhouse gases to the atmosphere.

One of the biggest outstanding issues is how much wealthy countries should pay to help poorer ones work towards building lower-carbon economies and adapt to some of the damage they've already suffered from climate change. NPR sat down this week with Achim Steiner, head of the United Nations Development Programme, to talk through the problem.

This interview has been edited and condensed.

Many people from these countries are really looking for help from the developed world. What's the background?

One main issue really in Glasgow is: Are we able to frame a co-investment pact here? The richer countries have already for years promised $100 billion a year as contributions towards hundreds of billions of dollars developing countries will have to invest in their energy systems. Almost 11 years after the promise was first made in the Copenhagen climate conference, it still hasn't been met. So, for developing countries, there is a growing sense of not only frustration, but a lack of trust. We are constantly being asked as developing nations to make higher commitments, and yet we see only limited progress in developed countries.

Why is that?

I think because we underestimate, first of all, what an immense effort developing countries have to undertake. Secondly, it's always difficult to take money that you would spend on yourself and invest it in someone else.

How much of this comes down to domestic political decisions in these developed rich nations?

Well, ironically, virtually everything that is being negotiated here comes down to national political dynamics, and this is where political leadership is really called for. Because if we simply decide the future of the world in terms of what my price per gallon of fuel is or how much electricity I'm being charged for, you essentially have a recipe for paralysis and for disaster.

Give me a sense of what it's like inside the negotiating room. Do you have developing nations lobbying very hard? What are the developed nations saying?

This is the "nerdier" part of the work, which is negotiating the details. How do we hold each other accountable? How do we create transparency? What are the baselines against which you measure the commitments of a country and how it is actually fulfilling them? That is often, I think, for the public difficult to appreciate. But without that, we don't have the transparency that allows us to have confidence in one another.

In terms of funding from the developed world to the developing world, can't that be measured by actually how much finance comes in?

You'd think so.

If you told me you were going to give me 10 bucks and 10 bucks didn't come in, you didn't fulfill your pledge.

Yeah, but the question is, do the 10 bucks come from your government sending you a check? Does it come through your bank where you have to borrow, maybe at a lower interest rate? Is it a grant?

That sounds very messy.

That's why it has been a struggle.

If developing countries did not get what they consider at least sufficient for now, what would be the implications and the stakes of that?

Some countries would simply revert back to saying, "Well, never mind, we'll just do business as usual."

And we'll just keep polluting as much as we want.

Exactly, because we've given up and we don't have the means to do something about it.

NPR's London Producer Jessica Beck contributed to this report.

This story originally appeared on the Morning Edition live blog.