Humans must drastically curb carbon emissions in the coming decades or face environmental catastrophe, as temperatures are expected to climb to levels that scientists predict would radically alter the earth's climate by the end of the century.
Luckily, the transition from an economy powered by coal, gas and oil to one fueled by low-carbon renewables has already begun.
Half of all new power plants built last year produced green energy, in what is one of the "clear signs that an energy transition is underway," the International Energy Agency said in a report published Tuesday.
Renewables are now the second-largest source of electricity after coal, according to the 28-country organization's 2015 World Energy Outlook report. Renewables are set to overtake coal as the largest source of electricity generation by the early 2030s, the report said.
By 2040, the European Union is expected to generate 50 percent of its electricity from renewables, China and Japan should hit 30 percent, and the United States and India plan to surpass 25 percent.
But this is no time to rest on laurels.
The United Nations' COP21 climate talks are set to begin in Paris at the end of the month. While a growing number of corporations and countries have pledged to reduce their emissions, global temperatures are still expected to rise to unsustainable levels.
Even if countries fully enact their latest pledges to reduce carbon emissions, average temperatures will rise by 2.7 degrees Celsius by 2100, according to data cited by Bloomberg from Climate Action Tracker, a joint venture between four European institutions. Scientists predict that a temperature increase above 2 degrees Celsius will radically alter the planet, melting glaciers, increasing sea levels and making weather more extreme and less predictable.
"As the largest source of global greenhouse-gas emissions, the energy sector must be at the heart of global action to tackle climate change," Fatih Birol, the agency's executive director, said in a statement. "World leaders meeting in Paris must set a clear direction for the accelerated transformation of the global energy sector."
That transformation is gaining steam as a groundswell of companies vows to quit carbon.
The number of companies putting a price on their own carbon emissions tripled since last year, according to a report released in September by the environmental data nonprofit CDP. Assigning a cost to the production of greenhouse gases establishes a financial incentive for companies to wean themselves off fossil fuels.
To boot, an unlikely coalition of corporate behemoths earlier this year pledged to transition to 100 percent renewable energy, with several expecting to reach that goal in the next decade.