Paul Hockenos is a Berlin-based writer, author of several books on Europe including most recently Berlin Calling: A Story of Anarchy, Music, the Wall and the Birth of the New Berlin. The opinions in this article belong to the author.

(CNN) Germany's Angela Merkel is often referred to as the "climate chancellor" because of her impassioned stand on climate protection, which has included the muscular arm-twisting of laggard nations in Europe and beyond -- as she demonstrated at the G20 summit in Hamburg in earlier this month.

And during her three full terms in office, she's guided Germany's vaunted Energiewende, or renewable energy transition, which has vastly increased the number of renewables in the power mix to make up a third of the country's electricity supply today -- and an astounding 85% of power generation on particularly sunny, windy days.

But Germany's headline success story has a dark underside that is usually overlooked in all the fanfare. Greenhouse gas emissions in Germany have not sunk significantly since 2009, but rather have stagnated at about 900 million tons of carbon dioxide a year: the highest in Europe by far. (France's, for example, are less than half as much.)

More renewables come online everyday in Germany -- boosted recently by the mighty contribution of a new fleet of state-of-the-art offshore wind turbines in the North and Baltic Seas. And the government's entirely realistic goal is that at least 60% of all energy, including heat and transport, should be green by 2050.

But, stubbornly, emissions refuse to budge. In fact, Germany is in real danger of not meeting either its 2020 or its 2030 emissions targets , the kind of goals it has pushed other countries to adopt.

If even Germany can't live up to its obligations, the international goal set at the 2015 Paris climate summit of keeping the rise in global temperatures below two degrees Celsius simply isn't realistic.

Germany's dirty secret underscores the inevitable conclusion that renewables are alone not enough to beat global warming.

There are other fronts just as critical in the battle to halt rising temperatures across the world, such as phasing out coal, pricing carbon emissions, reducing consumption, and rethinking our transportation systems. In these areas, the ostensible wunderkind of Germany is a delinquent, not the pioneer it could be.

JUST WATCHED Former UN climate chief on Paris deal, Trump Replay More Videos ... MUST WATCH Former UN climate chief on Paris deal, Trump 07:20

Berlin, however, isn't alone, either in failing to sink emissions or living the illusion that more solar panels, hydro-power plants, and wind turbines will solve the problem while also fueling a booming industry that creates jobs and revenue.

Germany -- and other countries too -- can begin to redress this glaring deficit in climate policy by grabbing the bull by the horns and going to the source of the problem: greenhouse gas emissions themselves. The Paris Agreement took a crucial step in this direction by setting emissions targets for individual sectors, such as energy, transportation, agriculture, and industry.

There's no better place to start than coal, particularly carbon-intensive among fossil fuels. Germany has more coal-fired plants than any other country in the EU.

Germany's electricity sector, more dependent on coal than renewables , accounts for over a third of the nation's carbon emissions. Germany could end subsidies to the industry and, as the Green Party advocates, pledge to exit coal completely by 2030. But so far, Berlin hasn't even stopped the construction of new coal plants (although the oldest ones are being shuttered.)

Resistance to such an offensive course lies not only in the industrial lobbies of the conservative parties, such as Merkel's Christian Democrats, but also Germany's biggest leftist party, the Social Democrats (SPD), which fears the loss of jobs in regions that have long voted SPD.

JUST WATCHED France makes edits to US climate video Replay More Videos ... MUST WATCH France makes edits to US climate video 01:21

Carbon emissions are still rising in Europe's transport sector, led by Germany, the main culprits being diesel fuel-powered vehicles, luxury cars, and road freight transport. Germany coddles its world-class automobile industry, which has been extremely slow to embrace alternatives to the combustion-fueled engine. Despite new lines of electric cars -- long after Tesla and other foreign carmakers forged ahead -- the Germans remain wedded to their big gas guzzlers.

Just last week Germany's powerful lobby group Association of the Automotive Industry (VDA) issued a communiqué entitled "Banning Combustion Engines Is the Wrong Line to Take," which argued that prioritizing alternative, low-carbon mobility over conventional automobiles is unfair and harmful to German industry.

Berlin has even intervened at EU level to water down regulations to sink automobile emissions over time. Nothing better illustrates the industry's attitude than the scandal over VW and other carmakers cheating on diesel emissions tests, which the German government turned a blind eye to in the first place, and still drags its heels in ending.

The option of putting serious prices on industrial emissions, coal burning, and high-pollution automobiles is one way forward. There are punitive pricing systems currently in place, but the cost to polluters is far too low to act as a real deterrent.

The EU's emissions trading scheme, a cap-and-trade permit system to regulate industry pollution, hasn't worked for years. Getting it on its feet would be a decisive move in making emitters pay, providing dollars-and-cents motivation to cut energy use and switch to renewables.

Lastly, Germany and the rest of the developed world have to critically examine their societies' levels of consumption. The world's current volume of consumption and economic growth are unsustainable as our population expands -- a fact that most economists and climate scientists agree on. But the lion's share of politicians either won't face this fact or are too timid to address it publicly, fearing a voter backlash when it comes to readjusting lifestyles.

Germany may not be the leader of the free world, as is sometimes claimed, but it is Europe's leading force and could trailblaze on climate protection as it has on renewable energy on a global scale. But first it has to be credible with much greater efforts at home. Others are likely to follow, just as they have on renewables.