MELBOURNE ― Humanity has just about run out of time to address climate change. Scientists have pointed out that a rise in temperature of 2 degrees Celsius above pre-industrial levels will put the Earth in dangerous, uncharted territory. Yet we currently are on a path toward an increase of 4 degrees or more this century. The last chance for action has arrived.

That chance lies in Paris in December 2015, when the world’s governments meet for the 21st annual United Nations climate-change meeting. But this time will be different. Either governments will agree to decisive action, as they have promised, or we will look back at 2015 as the year when climate sanity slipped through our fingers.

In 1992, the world’s governments adopted the U.N. Framework Convention on Climate Change, promising to avoid “dangerous anthropogenic (human-induced) interference in the climate system” by reducing the rate of emission of greenhouse gases, especially carbon dioxide. But, though the treaty entered into force in 1994, the rate of emissions of greenhouse gases, including CO2, has actually increased.

In 1992, global combustion of coal, oil, and gas, plus cement production, released 22.6 billion tons of CO2 into the air. In 2012, the most recent year for which comparable data are available, emissions were 34.5 billion tons. Humanity has accelerated, rather than controlled, human-induced climate change.

This is now the greatest moral issue of our time. Global fossil-fuel use gravely threatens the poor, who are the most vulnerable to climate change (though the rich are the main cause), and future generations, who will inherit a planet that has become unlivable in many places, with food supply subject to massive shocks.

We are causing this harm in an age when technological breakthroughs enable the world to shift from dangerous fossil fuels to low-carbon energy sources, such as wind, solar, nuclear, and hydro, and reduce the impact of fossil fuels by using carbon capture and storage (CCS) technology. Pope Francis recently put it just right: “Safeguard Creation,” he said. “Because if we destroy Creation, Creation will destroy us! Never forget this!”

Yet, for the many powerful interests, climate change remains a game, with the goal being to delay action for as long as possible. The giant fossil-fuel companies have continued to lobby behind the scenes against the shift to low-carbon energy, and have used their vast wealth to buy media coverage designed to sow confusion. Rupert Murdoch’s media empire in the United States, the United Kingdom, Australia, and elsewhere stands out as playing a particularly cynical and harmful role in spreading anti-scientific propaganda.

Even so, the politics of climate change may be changing for the better ― a change reflected in the Pope’s forceful message. Here are six reasons why the stalemate might soon end.

First, the world is waking up to the calamity that we are causing. Though the Murdoch propaganda machine churns out a daily stream of anti-scientific falsehoods, the public also sees prolonged droughts (now in parts of Brazil, California, and Southeast Asia, to name a few places), massive floods (recently in Bosnia and Serbia), and lethal heat waves (in many parts of the world).

Second, the world’s citizens do not want to go down in flames. Public opinion has so far succeeded in blocking the construction of the Keystone XL Pipeline, which would accelerate the production of Canada’s oil sands ― a shocking prospect, given that neither Canada nor the U.S. yet have committed to a climate plan.

Third, more severe climate shocks may lie ahead. This year could prove to be a major El Nino year, when the waters of the Eastern Pacific warm and create global climate disruptions. A big El Nino now would be even more dangerous than usual, because it would add to the overall rising trend in global temperatures. Indeed, many scientists believe that a big El Nino could make 2015 the hottest year in the Earth’s history.

Fourth, both the U.S. and China, the two largest emitters of CO2, are finally beginning to get serious. President Barack Obama’s administration is trying to stop the construction of new coal-fired power plants, unless they are equipped with CCS technology. China, for its part, has realized that its heavy dependence on coal is causing such devastating pollution and smog that it is leading to massive loss of life, with life expectancy down as much as five years in regions with heavy coal consumption.

Fifth, the Paris negotiations are finally beginning to attract global attention from both the public and world leaders. U.N. Secretary-General Ban Ki-moon has called for political leaders to attend a special summit in September 2014, 14 months ahead of the Paris meeting, to launch intensive negotiations. The U.N. expert network that I direct, the Sustainable Development Solutions Network (U.N. SDSN), will issue a major report in July on how each of the major economies can successfully decarbonize the energy system.

Finally, technological advances in low-carbon energy systems, including photovoltaics, electric vehicles, CCS, and fourth-generation nuclear power with greatly enhanced safety features, all help make the transition to low-cost, low-carbon energy technologically realistic, with huge benefits for human health and planetary safety.

Starting this fall, the U.N. SDSN will create a platform for all global citizens to participate in the hard work of saving the planet. The SDSN will offer a free, online introductory course to climate change, and then host a global online “negotiation” of a global climate agreement.

We expect that hundreds of thousands, perhaps millions, of interested citizens worldwide will participate online, showing the way for the politicians. The control of climate change is a moral imperative and a practical necessity ― far too important to be left to politicians, Big Oil, and their media propagandists.

By Jeffrey D. Sachs

Jeffrey D. Sachs is professor of sustainable development, professor of health policy and management, and director of the Earth Institute at Columbia University. He is also special adviser to the United Nations secretary-general on the Millennium Development Goals. ― Ed.

(Project Syndicate)