The European Union (EU) has announced plans to levy a tax on airline emissions for all planes landing and taking off from EU airports. This tax would be calculated not only based on mileage flown in EU airspace but also for the entire length of the flight (thus, Chinese and Japanese airlines would be taxed for an entire journey from Beijing or Tokyo).

It's tempting to call the shameful taxpayer subsidy for electric cars - vehicles that are unaffordable for all but a small number of wealthy Americans - this nation's costly little secret.

Once again, the regulators in California have decided to lead the nation in terms of vehicle emission standards, proposing to require that 15.4 percent of all vehicles sold by 2025 must be electric cars, plug-in hybrid cars, or (currently non-existent) fuel cell cars.

President Obama has chosen to downplay the lack of freedom in China. By doing so, he gives up on a vital prerequisite for an effective, credible emission-control regime.

The United Nations conference in Copenhagen will follow in the hypocritical footsteps of Kyoto, with countries declaring their resolution to curb GHG emissions while at the same time either refusing to pay the costs or claiming exemption from controls.

The chances of seeing a properly valued, revenue-neutral carbon tax are about as likely as the chances of seeing a unicorn-powered spaceship. The idea would cause nothing but misery. Here are a few reasons why:

A debate over policy responses to greenhouse gas emissions.

When economies are already laboring under too much spending, and are at diminishing-return levels of taxation, implementing a carbon tax would be a mistake.