Unless profound changes are made, global warming will only get worse, according to the United Nations. If greenhouse gases are allowed to grow at their present rate, then much more expensive technology will be required to fight carbon dioxide in the future, the Intergovernmental Panel on Climate Change warns. The next 15 years will be especially crucial when it comes to determining whether global warming can be limited to 2C (3.6F) by 2100, the report also warns. The IPCC's full report is set to be released in April, but the UN says the draft was leaked Friday.

The report is rather damning: It points a finger to governments that have spent more on fossils fuels than clean technology, says that even increased conservation efforts may not stunt environmental damage, and reveals that "CO2 gases grew by 2.2 percent per year on average in 2000-2010 — almost twice as high as in 1970-2000."

And worse of all, emissions are predicted to double or triple by 2050 unless "explicit efforts" are made. In 2009, an earnest effort was made when climate leaders vowed to keep global warming from increasing by two degrees, even in the face of rising population numbers and haphazard economic growth. This requires carbon dioxide concentrations to be kept in check — below 530 parts per million — even though the latest readings place the level at roughly 400 parts per million. And that's costly:

The experts estimated that in order to stabilize the atmospheric concentration of CO2 between 430 and 530 parts per million, investments in fossil fuels would have to decline by $30 billion a year between 2010 and 2029, while investment in non-carbon producing energy sources would have to rise by $147 billion a year.

Seven countries have caused 60 percent of the world's warming, with the United States responsible for about a fifth of all global warming since the mid-1700s. China, Russia, Brazil, India, Germany, Britain, France, Indonesia, and Canada round out the top 10 culprits. Even though the United States is the biggest contributor, more Americans don't believe global warming even exists. In a recent Yale survey, the number of people who say they do not think climate change is happening rose seven percentage points to 23 percent by November 2013.

The UN urges us to act now. If not for yourself, do it for the polar bears.

Image via The Center for Climate and Security