Hooray: Besides all the unintended consequences, gaming the system, and outright fraud, a decade of the UN CDM bad-weather-preventing program has allegedly prevented half a day's worth of natural greenhouse gas emissions

Clean Development Mechanism passes one billion credits mark | RTCC - Responding to Climate Change

The one billionth certified emission reduction credit under the Kyoto Protocol’s Clean Development Mechanism (CDM) will be issued today, according to the UN climate secretariat (UNFCCC)...This effectively means that it has now prevented the emission of a billion tonnes of CO2 into the atmosphere.
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“This exciting milestone is a testament to the expanding use of the CDM,” said UNFCCC Executive Secretary Christiana Figueres.
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In 2008 David Victor, a leading carbon trading analyst at Stanford University in the US, argued that as many as two-thirds of the supposed “emission reduction” credits being produced by the CDM from projects in developing countries were not backed by real reductions in pollution.

Flashback:  Incentive to Slow Climate Change Drives Output of Harmful Gases - NYTimes.com

So since 2005 the 19 plants receiving the waste gas payments have profited handsomely from an unlikely business: churning out more harmful coolant gas so they can be paid to destroy its waste byproduct. The high output keeps the prices of the coolant gas irresistibly low, discouraging air-conditioning companies from switching to less-damaging alternative gases. That means, critics say, that United Nations subsidies intended to improve the environment are instead creating their own damage... Since the United Nations program began, 46 percent of all credits have been awarded to the 19 coolant factories, in Argentina, China, India, Mexico and South Korea. Two Russian plants receive carbon credits for destroying HFC-23 under a related United Nations program.

“I was a climate negotiator, and no one had this in mind,” said David Doniger of the Natural Resources Defense Council. “It turns out you get nearly 100 times more from credits than it costs to do it. It turned the economics of the business on its head.” 

NASA JPL site: Science

Fossil fuel combustion and other human activities are currently emitting about 30 billion tons or 30 Gigatons of CO2 into the atmosphere each year. So for each ton of carbon that is put in, we get 3.7 tons of CO2. This is only a small fraction (4%) of the 770 Gigatons of CO2 emitted into the atmosphere each year by natural processes in the ocean and on land.