Outside the Paris climate conference center, organizers have erected a ‘Wind Tree’ (Arbre a Vent) which produces electricity using the power of the breeze. In doing so, they have summed up exactly what is wrong with the conference.

The tree will only produce 3,500 kWh per year and it costs about €25,000. So, at a production price of about 7 cents per kWh, it will take 89 years to make up just the capital cost. Or put differently, the cost is 300% more expensive than even traditional wind power, which still struggles without subsidies.

The COP21 conference is about symbolism: spending a lot of money to feel good but do very little.

This week the cynicism reached new heights, when Christiana Figueres, executive secretary of the UN Framework Convention on Climate Change, signed a declaration led by the Philippines and other governments stating that temperatures should be capped at a 1.5 degree Celsius rise, instead of the 2 degree Celsius target many had been talking about. The French hosts endorsed the idea. Environmental journalists reported this news with straight faces, and activists declared that keeping temperatures under 1.5°C was indeed the “moral” thing to do.

The cynicism from everyone involved is breathtaking. With an already impossible-to-achieve goal on the table, the head of the United Nations climate body and many others who equally know better are purporting to believe that the world should pursue an even more far-fetched target.

The target of 2°C has become a touchstone of climate campaigners, to the point where many people believe that it’s some sort of tipping point identified by scientists, past which the planet collapses into a fiery ball.

It appears to stem from a William Nordhaus paper from 1977, in which the economist made the case that a rise of two degrees would put the earth’s climate outside the Earth’s range of temperature over several hundred thousand years.

Since then, it’s been driven by a political agenda, not scientific analysis. The two-degree limit isn’t mentioned in a single report by the United Nations Intergovernmental Panel on Climate Change – the world’s climate scientists.

Climate economist Richard Tol analyzed the target in 2007, in a paper published in Energy Journal. “In sum,” he wrote, “the official documents that justify the 2°C warming target for long-term climate policy have severe shortcomings. Methods are inadequate, reasoning sloppy, citations selective, and the overall argumentation rather thin. This does not suffice for responsible governments, answerable to the people, when deciding on a major issue.”

As University College London Professor of Climatology Mark Maslin told the Wall Street Journal this week, “it’s not a sensible, rational target because the models give you a range of possibilities, not a single answer.”

The fundamental problem with the two degree target, though – and the reason why the statements from the likes of Figueras are mind-blowing -- is not that it is arbitrary and political. It’s that reaching it is impossible. Most economic models show this, and most people engaged with climate science understand this.

Professor David Victor from the University of California, San Diego and Professor Charles Kennel from the Scripps Institution of Oceanography, wrote recently in Nature that the few economic simulations that show that capping rises at 2 degrees Celsius could just be possible “make heroic assumptions — such as almost immediate global cooperation and widespread availability of technologies such as bioenergy carbon capture and storage methods that do not exist even in scale demonstration.”

Professors Victor and Kennel make the case that instead of chasing an arbitrary temperature rise figure, we should track an array of planetary ‘vital signs’. This makes sense.

Except, rather than taking that smarter path, figureheads like Ms. Figueras are pursuing an even more quixotic ambition: limiting temperature rises to 1.5 degrees Celsius.

It should hardly need explaining that if 2 degrees Celsius is impossible, an even more stringent limit is also impossible.

The temperature effects of the Paris climate promises for 2016-2030 from the world’s governments will be rises just 0.05°C (0.09°F) lower than they would have been by 2100. The cost for the Paris climate treaty to achieve just that is at least 1 trillion euro a year by 2030; even just trying to embrace a target of 1.5°C would be ruinously expensive.

Just like with the Wind Tree, the 1.5 degree target is symbolism at its emptiest.