Editor’s Note: Helen Mountford is the vice president for climate and economics at World Resources Institute, which works to identify and advance the structural shifts needed to address climate change. She was previously the deputy director of environment for the Organization for Economic Co-operation and Development. The opinions expressed in this commentary are solely her own. View more opinion articles on CNN.

CNN  — 

On Friday, countless young people will flood the streets of the world’s major cities, demanding action to tackle climate change. The global movement stems from the stark reality that the window to addressing this emergency is closing. At the front of these demonstrations, there is frequently a banner warning that there are just “12 years to save the Earth.”

Helen Mountford

If political leaders finally respond to the climate crisis, we may well have these youthful advocates to thank. But there is a problem with this timeline: We don’t have 12 years to jump-start action on climate change – we have just one.

According to an article in the journal Nature, global greenhouse gas emissions must peak no later than next year and rapidly decline thereafter for us to have a good chance of preventing increasingly severe consequences from the climate crisis – everything from imperiled croplands, flooded communities and widespread disease. Delaying any longer will push us toward an ecological tipping point, with no way for humanity to claw its way back out.

Next year is also a critical point because it is when country leaders agreed to put forward new climate plans when they adopted the Paris Agreement in 2015. They knew that the climate action commitments in Paris would not be enough, and so they agreed to come back in five years to step up their efforts. We will soon find out if prime ministers and presidents will stand by their word. Collectively, these revised plans will point humanity to a future that is either bright or bleak.

Right now, the picture looks bleak.

Deforestation is increasing, with 12 million hectares of tropical forest chopped down last year. Coal plants are still being built in at least 30 nations. Every year, countries prop up the coal, oil and gas industries with more than $5.2 trillion in subsidies, tax breaks and unaccounted costs of fossil fuel use in 2017. Ford sold nearly 1.1 million F-150 trucks last year (one every 29.3 seconds) even though the pickup gets a paltry 19 mpg.

Earlier this month atmospheric carbon dioxide concentrations hit 415 parts per million for the first time in human history; the last time levels were that high was during the Pliocene Epoch when there were trees at the South Pole and sea levels were 20 meters higher than they are now.

I could go on. Clearly, the world is not yet making the urgent and unprecedented changes needed to halt global warming.

In a landmark UN climate report released last year, scientists found that a global temperature rise of just 1.5 degrees C (2.7 degrees F) over preindustrial levels would greatly increase the risk of drought, floods and extreme heat, and food supplies would be in jeopardy even as the global population steadily rises. Every iota of warming leads to even more catastrophic consequences.

No one expected the national climate plans submitted in 2015 to solve the problem. In fact, even if all the Paris commitments are realized, global temperatures would still be on track to rise 2.7 to 3.7 degrees C (4.9 to 6.7 degrees F) in the next century. Climate change is humanity’s largest challenge; it would be sheer hubris to think we would fix it in one fell swoop. The beauty of the pact is that it calls for countries to come back to the table every five years – in 2020, 2025 and so on – with new plans informed by the latest advances in high-tech, science and shifting markets.

Economic, technological and market trends since 2015 provide a compelling case for countries to strengthen their climate plans next year. And there are promising signs that industries are making environmentally friendly shifts. Renewable energy is now cheaper than fossil fuels nearly everywhere and accounts for nearly two-thirds of new electricity capacity.

More affordable energy-storage options are making wind and solar attractive options, even when the wind doesn’t blow and the sun sets. Plummeting battery prices are expected to make electric cars cheaper than gas cars just three years from now. And the F-150 pickup? Ford is planning for it to go electric, too. The rapid decline of the internal combustion engine – and how quickly leading car manufacturers have committed to clean solutions – caught everyone by surprise.

Other major companies are also shifting their business models to seize the opportunities of the zero-carbon transition, with more than 550 businesses setting or committing to set bold emission reduction targets informed by climate science. And in recent years the very concept of climate action has shifted from a potential burden to a major economic opportunity as countries compete in the race for the $26 trillion in benefits from bold climate action between now and 2030.

To prepare for the major moment of truth in 2020, world leaders are gathering at the UN Climate Action Summit in September in New York. UN Secretary-General Antonio Guterres has set a clear benchmark for success by challenging countries to present concrete plans to strengthen their climate commitments and make them compatible with the Paris goal of limiting temperature rise to 1.5 degrees C.

This summit is a wake-up call for heads of state, ministers, mayors and business leaders to get ready to up their game. It is also an opportunity to show the rising generation of climate activists such as Greta Thunberg how – this time – world leaders will keep their promises.

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    Now is the time to jump-start climate action and get on a path to a brighter future. Countries have just one year to step forward with bigger, bolder commitments that respond to the scale of the climate crisis.

    Our children are in the streets demanding a world worth living in. Let’s give it to them.