The conservative American Enterprise Institute projected Tuesday that the Green New Deal would cost the economy nearly $9 trillion a year, while doing little to meet United Nations climate targets.

In comparison, the total U.S. economy is about $21 trillion, as measured by Gross Domestic Product.

In a draft analysis of the "Green New Deal" resolution — which is a broad outline and doesn't have specifics — the think tank said its 100 percent renewable energy target would, conservatively, cost just over $490 billion per year to implement.

Ben Zycher, AEI's senior energy analyst and author of the report, explained in the report that the renewable energy goal would also cause significant environmental damage from the amount of land that would have to be dedicated to wind farms and solar panels to meet the goal.

The number of renewable energy facilities needed to meet the 100 percent renewable energy goal would take up 115 million acres, or a land mass 15 percent larger than the state of California, the analysis finds.

But the Green New Deal's other social programs, such as a government-financed healthcare system and guaranteed employment, would balloon the cost of the plan to $9 trillion per year in lost economic growth, in addition to the renewable energy costs. Much of the cost would come through the higher taxes needed to finance the government programs.

Yet, the plan would have only a minimal effect on the rate of global warming, according to the analysis.

"The future temperature impacts of the zero-emissions objective would be barely distinguishable from zero: just a 0.173°C difference by 2100," said Zycher.

The Green New Deal's central premise is that global temperatures must be kept below 1.5 degrees Celsius by mid-century in order to avoid the most severe effects of climate change.

To achieve that goal, which was outlined by the U.N.'s intergovernmental climate panel last year, it would require the U.S. to produce net-zero carbon emissions by 2050.

Net-zero refers to the process of eliminating as many carbon emissions as are produced within the country, through activities such as forest restoration and the deployment of carbon capture technologies.