In 2009, Latin American nations might have been forgiven for wondering why they should concern themselves with international climate negotiations. That was the year United Nations-led climate talks in Copenhagen collapsed with no legally binding reductions of greenhouse gas emissions. Civil society groups and governments alike reacted with disbelief. The so-called Copenhagen Accord, signed by the U.S., China, India, Brazil and South Africa, called for limiting global temperature increases to 2 degrees Celsius above pre-industrial levels by 2050, yet imposed no legal obligations for achieving that goal. John Sauven, Greenpeace’s executive director for the United Kingdom, captured some of the frustration. “The city of Copenhagen is a crime scene tonight with the guilty men and women fleeing to the airport,” he told the press. “There are no targets for carbon cuts and no agreement on a legally binding treaty.”

Five years later, developing and developed nations alike among the 193 signatories to the UN Framework Convention on Climate Change (UNFCCC) are hopeful that international climate efforts might be getting back on track. Starting on Dec. 1, negotiators will hold 12 days of UN talks in Lima, Peru, to shape the legal architecture of a successor agreement to the Kyoto Protocol, which expires in 2020. The choice of venue underscores how Latin countries, though divided on some key climate-policy questions, are becoming increasingly engaged in the global response to climate change, a phenomenon already exerting powerful impacts on Latin America. A core group of them aims to press in Lima for every nation, regardless of economic-development status, to determine its responsibility for reducing greenhouse-gas emissions and to argue that wealthier countries must adequately assist poorer ones in the fight against global warming. The talks, which could lead to a draft text, are intended to lay the foundation for final negotiations in Paris in 2015.

Recent events have given Lima conferees reason for hope. On Oct. 23, the European Union agreed to reduce its current emissions 40% by 2030, an apparent show of goodwill in advance of the Lima talks. Then on Nov. 10, China and the United States made history with their first-ever commitments on emissions-reduction. The United States pledged to cut its net emissions 26% to 28% below 2005 levels by 2025, and China agreed that by 2030, it would boost non-fossil fuels to 20% of its energy portfolio and begin reducing its greenhouse-gas output in absolute terms.

“This is a very welcome signal politically,” says Alejandro Rivera, a Mexican negotiator for the Lima talks. “It makes little sense, either in Mexico’s view or that of most of the other parties, to create a regime for the post-2020 period without the participation of the world’s two biggest emitters.”

Latin American nations will try to build on that momentum to influence the outcome of the upcoming talks, analysts say. They will try to push the U.S., China and other big emitters to further curb emissions and request more money for the Green Climate Fund. The fund, which provides developing countries with support for climate mitigation, was given US$9.3 billion in pledged investment at a Nov. 20 meeting of wealthy nations in Berlin. But the Copenhagen Accord stipulates it should have $100 billion by 2020, and most Latin leaders believe it should have far more.

On other critical issues, the region is sharply divided. The issue of shared responsibility for emissions reduction is a prime example. Along with Mexico, a grouping of six Latin American nations called the Independent Alliance of Latin America and the Caribbean (Ailac) has taken the position that emissions reduction after 2020 should be the responsibility of all countries—not developed nations alone, as under the Kyoto Protocol.

Mexico and the Ailac countries—Chile, Colombia, Costa Rica, Guatemala, Panama and Peru—believe each nation should determine its own emissions-reduction targets, but that those targets should be subject to a regimen of monitoring, reporting and verification. They also argue such targets should reflect countries’ historic responsibility for producing greenhouse emissions and their capacity for mitigating them, with the more industrialized, richer nations making a greater effort.

These positions do not sit easily with the Bolivarian Alliance for the Americas (Alba), a grouping of nations including Bolivia, Cuba, Ecuador, Nicaragua and Venezuela. Alba, along with Brazil, resists the idea of targets for developing nations.

Another dividing point is the use of markets to finance clean energy and forest conservation projects. After Asia, Latin America has been the biggest beneficiary of the Clean Development Mechanism (CDM), a Kyoto Protocol program through which industrialized nations offset their emissions by financing emissions-reduction projects in the developing world. The CDM has suffered serious setbacks over the past five years, including a 95% drop in emissions-reduction prices on its market, but has directed hundreds of millions of dollars to clean-energy projects in Latin America nonetheless. Ailac and Mexico would like to see continuation of an improved market mechanism in any successor agreement to the Kyoto Protocol. Bolivia is vigorously opposed, seeing market mechanisms as an example of capitalist exploitation through which the developed countries avoid curbing their own emissions at home.

“Latin America as a whole may agree that climate change is a massive threat and that it must be dealt with through the UNFCCC, but it does not speak with one voice,” says Guy Edwards, an expert on international climate policy at Brown University.

Bringing urgency to the debate among Latin nations is the fact that Latin America is among the world’s most vulnerable regions to climate change and already is grappling with the impacts. Over the last decade, intense rains and flooding have pummeled Mexico, Colombia, Brazil, Bolivia and Argentina. Droughts have seared large parts of Colombia and Venezuela. Images in March and April from Colombia’s Orinoco River watershed of thousands of dead cattle, capybaras, and crocodiles strewn across the parched savannahs as temperatures hit 40 to 45 degrees Celsius (104 to 113 degrees Fahrenheit) tell only part of the story, analysts say. Thousands of people have died in Central America and the Caribbean over the last decade from hurricane-triggered landslides and flooding. While it is difficult to associate individual meteorological events directly with climate change, green advocates cite scientific evidence that overall, global warming already is making its presence felt in the severity of the region’s weather events. “When we talk about climate change, we’re not just talking about the future, we’re talking about today,” says Mariana Panuncio, World Wildlife Fund (WWF) climate change director for Latin America and the Caribbean.

The future holds far worse. According to recent projections by the UN Intergovernmental Panel on Climate Change (IPCC), temperatures by the end of the century will rise between 1.6 and 4 degrees centigrade in Central America and could surge as high as 6.7 degrees centigrade in parts of South America. As a result, the production of corn, beans, rice and other crops could be sharply curtailed, says the IPCC. Expected sea-level rises of up to 2 meters could menace highly populated coastal areas with flooding and erosion. Ocean warming and carbon-dioxide acidification could kill off the great Mesoamerican coral reef, which stretches 1,100 kilometers (700 miles) from the northern tip of the Yucatán Peninsula through the Honduran Bay Islands. Tropical glaciers in the Andes already have lost 15% of their surface area. Their continued retreat or disappearance, says the IPCC, could cause sharp reductions in potable water, irrigation, and hydroelectric generation for millions of people. Those impacts threaten the region’s efforts to improve its people’s welfare. Studies by the Inter-American Development Bank and other institutions show annual losses in crops, fishing, tourism and infrastructure, as well as from the increase in human disease, could exceed $110 billion by 2050, or 2.4% of the GDP of Latin America and the Caribbean, and surpass 5% of GDP by the end of the century.

“Climate change will ultimately put in jeopardy any development objectives Latin America has in terms of generating growing and thriving economies and lifting its people out of poverty,” says WWF’s Panuncio. “And that is not to mention the increasing impacts on habitat, species, and ecosystem services; if corals disappear, parts of the Amazon are turned into savannahs, and other natural systems experience large-scale transformations.”

Analysts say that no matter what their outcome, climate negotiations have helped to focus Latin America’s attention on global warming threats. The region’s nations over the last decade have devised energy-efficiency and forestry-conservation programs; restored mangroves to protect coasts against climate-induced storm surge; and developed hardier crops and new technologies for conserving high-mountain ecosystems and retaining water.

They also have created new legislative frameworks and institutions. In 2012, Mexico, the second biggest emitter of greenhouse gases in Latin America after Brazil, became the first developing country to pass a comprehensive climate-change law. In doing so, it committed to generating 35% of its electricity from renewable sources by 2024. A tax of $3.50 per ton of carbon dioxide took effect in January of this year for diesel, coal, propane and other fossil fuels. A national carbon registry, requiring all major polluters to report their emissions, will take effect in January 2015, and could lead to a nationwide emissions trading system.

Chile also has established climate goals, promising to cut its greenhouse emissions 20% below 2007 levels by 2020. In September, it approved a carbon tax, which in four years will require large factories and the electricity sector to pay $5 per metric ton of carbon dioxide emitted. Chile’s pipeline of solar and wind projects has grown, with US$7 billion investment this year alone. (See related story—this issue.)

Such advances, however, have occurred in the context of a heavily carbon-intensive regional economic model. While Latin American leaders have weighed in passionately in international forums on the need to fight global warming, most of them have continued to push vigorously for investment projects that perpetuate resource extraction, land-use change and fossil-fuel-based production and transport.

“There is a rather large chasm between rhetoric and reality,” says Brown University’s Edwards. “There have been many impressive flagship initiatives in the region and unquestionable progress. But with their focus on economic growth, Latin American countries also are embracing the expansion of oil, mining and other activities that contribute to deforestation and global warming.”

Deforestation is a prominent case in point. On Sept. 23, Colombia and Peru signed the New York Declaration on Forests during the UN summit, committing themselves to help halve the loss of natural forests by 2030. But an oil and mining boom over the last decade, stimulated by government incentives, has helped keep deforestation stubbornly high in Colombia at more than 120,000 hectares (295,000 acres) last year. And in Peru, land-use changes associated with agriculture, along with illegal gold mining and logging, have impacted much of the Peruvian Amazon, while leading to a nationwide forest loss of more than 240,000 hectares (590,000 acres) from 2001 to 2012.

Brazil and Costa Rica have won praise for gains in forest protection: Brazil for bringing down its deforestation rate by 80% from 2005 to 2010; Costa Rica for increasing its forest cover from 42% in 1997 to more than 52% today. But emissions from deforestation as well as from the transport and energy sectors soared last year in Brazil. And Costa Rica has done little to improve an aging transport system, heavily reliant on fossil fuels, that now accounts for 34% of its greenhouse-gas emissions.

Latin America stands to influence the climate talks in Lima. With its immense forests, savannahs, and glaciers, and emissions that still are only 11% of the world’s total, it has both moral authority and clout. But in the personal opinion of Alicia Villamizar, an IPCC author on Venezuela, the region must stop blaming the developed world for its climate change problems and “fulfill its commitments to fight the problem and improve the life of its peoples.”

Panuncio of WWF argues this can be achieved in part by moving faster on renewable energy before other more polluting technologies are locked in to Latin America’s development trajectory. WWF advocates a goal by which 45% of the region’s primary energy would come from renewables by 2030.

“The key question Latin American countries will bring to the negotiations is what kind of development they aim to have,” Panuncio says. “By that I mean not only what kind of development will be possible in light of the climate impacts the region could suffer depending on the trajectory of global emissions; I also mean whether or not Latin American countries will choose a low-carbon development path to guide their region into the future.”