Germany, for example, with the world's fourth largest economy, began a commitment 15 years ago to transition to renewable energy and at the same time to reduce energy consumption. Traditionally, energy consumption drops only during recessions; but Germany has maintained modest economic growth despite its low-carbon diet. In the words of World Bank President Jim Yong Kim, “Germany is the first country in the world to show that they can uncouple growth from burning fossils fuels.”

This leading-by-example approach became a template for the so-called “bottoms-up” tactic that led to the successful climate accord in Paris -- whereby 186 nations submitted their own carbon-reduction plans prior to the early December commencement of the 21st meeting of the Conference of Parties (COP21) of the United Nations Framework Convention on Climate Change.

It was in this spirit of encouraging other nations to set their own climate goals that U.S. President Obama defied his global-warming-denying Republican critics by using the EPA’s authority to regulate power plants’ greenhouse gas pollution. So, too, Obama crafted a carbon emissions reduction agreement bilaterally with Chinese President Xi Jinping.

Thus it is that the final agreement that emerged in Paris is based less on legal requirements imposed upon the signatory nations than on what’s been described as “global peer pressure.” “Name-and-shame” is another sobriquet. Although the individual countries’ climate goals are voluntary, whether the goals are being met is subject to transparent monitoring and verification.

Moreover, all signatories are committed to updating their plans with ever more aggressive targets so that the average global temperature rise since the Industrial Revolution be kept well below 2 degrees Celsius (3.6 degrees Fahrenheit). Making these targets even more urgent was the news that 2015 will likely be the hottest year ever recorded for the planet. Moreover, the 10 hottest years ever recorded have all happened within the last 20 years.

Holding the nations’ feet to the fire, so to speak, will be not only environmental activists and their non-profits but also businessmen who see profit in a carbon-free future as well as non-state governmental entities of municipalities, which account for an estimated 70 percent of global greenhouse gas emissions.

In this regard, Paris Mayor Anne Hidalgo and former New York City Mayor Michael Bloomberg co-hosted their own “mini-summit” in Paris for leaders representing almost 500 cities around the world. As for private enterprise, one American investor noted the fact that just having more global leaders at the same time in one place than ever before in history sends a powerful message: “Whoever continues doing business as usual will wither.”

The conference’s successful conclusion was an emotional moment, with delegates, tired from two weeks of negotiating, standing and applauding in both relief and joy. Praise was showered on the host nation of France, whose legacy of diplomatic skills had been very much in evidence and whose experience of a terrorist attack only two weeks before the conference began had made the climate negotiators’ efforts to forge international solidarity especially poignant.

“This demonstrates the strength of the French nation and makes us Europeans all proud,” said EU Energy and Climate Commissioner Miguel Arias Cañete.

Walter Nicklin, covering the Paris conference for European Affairs, is Publisher of the Rappahannock News and former reporter for the Economist