MEXICO CITY, Mexico — The communal lands outside San Juan del Rio are a world away from the plush boardrooms of Copenhagen. But here, in the heart of Mexico, the hard, dry earth has a secret to tell, one that could alter next month’s discussions on climate change and affect billions of people around the globe.

For almost two years, President Felipe Calderon has pushed hard to transform Mexico into a leading voice on environmental issues, hosting international summits on climate change and inviting climate guru Al Gore to discuss the dangers of inaction. In June, the president even pledged to cut 50 million tons of carbon dioxide emissions, or 7 percent, per year until he leaves office in 2012, a promise that stunned many of his fellow countrymen.

All the while, Calderon has portrayed Mexico as the rare developing country willing to do its part to fight global warming.

“We all should contribute, each to our own degree, what we can in this fight,” Calderon said in September. “This has caused some tension with our fellow developing countries … but we believe that we can find formulas that will allow everyone to contribute when it comes to this matter of life and death.”

But the president’s proposals have come under strong criticism here in Mexico, where a string of failed programs, scandals and delays have cast doubt on the government’s ability to fix its own environmental problems, let alone design international accords.

The president’s environmental program consists of two pillars: a forestry program called ProArbol and a proposed international “Green Fund” to finance projects intended to reduce greenhouse gas emissions.

ProArbol has come under particular scrutiny, its first two years plagued with poor results and charges of fraud. The program is charged with reforesting 400,000 hectares of forest per year, but a government audit found ProArbol only planted 341,000 in 2007, despite spending all of its funds.

Meanwhile, a Greenpeace investigation earlier this year found that only 8 percent of the trees ProArbol planted two years ago actually survived. In some cases, non-native trees were planted and quickly died, while in others, the trees were already sick or were planted at the wrong time of the year.

Rather than halt deforestation, ProArbol has only made it worse by pretending the problem is under control, said Hector Magallon, head of Greenpeace Mexico’s Forest Campaign. Mexico loses roughly 500,000 hectares of forest per year, ranking it among the five most heavily deforested countries in the world.

Like Calderon’s government as a whole, ProArbol has favored private companies — in this case timber companies and tree nurseries — over more effective, community-based solutions, said Magallon.

Cities like San Juan del Rio, once ringed by hearty forests, now fill with dust from the barren hillsides that surround them. The town of 1,000 sits at the foot of a mountain, its simple cinderblock houses clustered around a small lake. Dry, furrowed farms stretch out toward the highway. Above, the mountain slope looks barren and worn. The newspaper El Universal reported earlier this year that only two out of the 90 trees planted in 2007 by ProArbol in the community of El Coto, near San Juan del Rio, were still alive.

The real focus, however, of Mexico’s green makeover is Calderon’s “Green Fund.” The president has promoted the idea as a potential successor to the soon-to-expire Kyoto Protocol.

The fund would consist of $10 billion donated from all but the poorest of countries around the world. The amount each country contributes would depend on three factors: its GDP per capita plus its present and historical share of greenhouse gas emissions. Rich or developed countries could withdraw up to half of their contributions, while developing countries could withdraw twice their share.

If adopted, the Green Fund “will finance projects oriented toward reducing carbon emissions or capturing carbon from the atmosphere,” Calderon explained last month.

France, Britain and Germany have praised the Green Fund as a good idea. But many countries have balked at endorsing it, or insisted that it supplement a more rigorous, binding agreement on reducing greenhouse gases.

“Getting climate change and the environment onto the table rhetorically is not a small feat, so that has been a success,” said Shannon O’Neil, a Mexico expert at the Council on Foreign Relations. “But the question for the Calderon government over the next three years is: Will there actually be this investment?”

Mexico currently produces 650 million tons of greenhouse gases per year, or 1.5 percent of the world total, making it the 13th largest polluter.

Calderon has said the Green Fund will bring green technology to developing countries that ordinarily wouldn’t have the funds for such projects. But the fund also has its fair share of critics who say that it — like ProArbol — favors large, international corporations.

“The Green Fund doesn’t represent the transferring of technology, but rather the application of technology that’s in the hands of other countries,” said Rosario Perez, a professor of economics and environmental studies at the National Autonomous University of Mexico.

“The money will end up going to the international companies that build the projects,” said Perez, while Mexican businesses “won’t even learn anything, because the technology won’t belong to them.”

Ultimately, the Green Fund is just a finance mechanism, not a quick solution to climate change, said Roberto Cabral, assistant director for strategic financing at Mexico’s Secretariat for Environment and Natural Resources. Nor does it preclude any additional treaties or restrictions on emissions, he added.

And while some have called the Green Fund an attempt to distract attention from Mexico’s bloody drug war, Cabral says the government’s environmental reputation is beyond debate.

“Mexico’s global leadership on this issue is not something we’re searching for,” he said. “It’s a consequence of what we’ve been doing.”

Residents of El Coto might beg to differ.