A residential compound is seen during a smoggy day in Wujiaqu, Xinjiang Uighur autonomous region, November 19, 2013. Picture taken November 19, 2013 Reuters Climate change is a grim subject, with warming temperatures, melting ice caps, rising sea-levels, and more frequent and intense severe weather events all projected for the planet's not-so-distant future.

For many, the direness of the situation is a spur to action. Just last month, 400,000 people flocked to the streets of New York City for the People's Climate March, a clear message to policy makers that bigger changes are both needed and wanted. And mere days afterward, the United Nations held its 2014 Climate Change Summit, where leaders from around the world gathered to discuss their strategies for reducing carbon emissions and slowing down global warming.

For some authorities, though, the bad news is better swept under the rug.

In recent years, a number of US states have had disappointing records when it comes to producing, publishing, and using the best climate science. Here are a few of the offenders:

Nebraska

In 2013, a bill passed in Nebraska authorizing a $44,000 study on climate change in the state, with one important caveat: The researchers would only be permitted to examine "cyclical" climate change, the result of non-human events such as solar variations. In short, the researchers would not be allowed to factor human activity — by now almost universally acknowledged as the biggest driving factor of climate change — into account.

The bill was originally introduced by Sen. Ken Haar without the "cyclical causes" provision. But things took a downward turn when Sen. Beau McCoy introduced an amendment that took human activity out of the running.

In defiance of the bill, a group of climate scientists at the University of Nebraska–Lincoln refused to participate in the state-sponsored study and, instead, started their own. The results of their study were released in September, and painted a concerning picture, with projections of higher temperatures, more frequent severe weather events, and reduced snowpack and runoff water from the Rocky Mountains.

The state of Nebraska has since abandoned its own study, although the state's Climate Assessment Response Committee will still be required to select an independent study to present to the governor and state legislature with recommendations for future action, reports the Columbus Telegram.

South Carolina

A state-sponsored climate study was labeled ready for public review in November 2011, but it stayed under wraps for more than a year before it was finally released in March 2013.

The report, now available online on the South Carolina Department of Natural Resources (DNR) website, describes potential changes in temperatures, sea level, water resources, and habitat for wildlife, and also details a recent history of warming temperatures across the state, particularly from 1970 on, as shown in the chart below.

This chart shows temperatures recorded at South Carolina's Greenville-Spartanburg airport from 1895 to 2010. It shows an overall rise in temperature over the years. SC Department of Natural Resources The report was shelved following a series of changes in the DNR, most notably the ousting of former director John Frampton, who spearheaded the study. South Carolina newspaper The Post and Courier reported that the report wasn't presented to the DNR's board until July 2012, and it wasn't publicly released until months later.

While the report was still being withheld, South Carolina news outlet TheState.com reported that "DNR officials say that their priorities have changed and that there is less urgency to release the study, which they say needs some revision."

North Carolina

North Carolina made headlines two years ago when it passed a bill prohibiting policy makers from basing coastal policies on the latest climate science.

The law was passed in June 2012 in response to a 2010 state-sponsored report compiled by the Coastal Resources Commission predicting a 39-inch rise in sea level by 2100 — bad news for tourism and real estate, alike. The chart below, taken from the report, illustrates the projected sea level rise throughout the rest of the century:

This chart shows projected sea level rise in North Carolina through 2100. The different lines represent different models for how fast sea level rise is expected to speed up throughout the century. The panel that completed the report predicts sea level to rise anywhere from 15 to 55 inches, and recommends that policy makers anticipate a 39-inch rise when making decisions for their communities. NC Coastal Resources Commission Now, at least until 2016, the law stipulates that coastal policies can only be made using sea-level predictions based on historical data, meaning data that do not account for melting ice caps and other likely climate-related events that could lead to accelerated sea level rise in the future. The law also requires the Coastal Resources Commission to write a new report including sea-level projections only through the next 30 years, to be updated every five years. The report is expected to be completed by March 2015.

Sadly, these aren't the only states slacking on their climate action, although they are among the most extreme. ThinkProgress published a map several months ago identifying 15 states that are governed by climate deniers and eight more whose governors take no stance or have weak climate policies.

This map, published by ThinkProgress, shows the US state governors' stances on climate change. States that are colored red with black stripes are governed by climate change deniers. Think Progress

The problems don't end with the states. The US federal government, in fact, has a history of covering up troubling climate science.

In 2005, The New York Times broke a story about a White House official who edited government climate reports repeatedly in 2002 and 2003 in order to downplay links between greenhouse gas emissions and climate change.

It seems that altering, downplaying, or just plain ignoring the most current climate science is sometimes easier for policy makers than facing the tough truths about climate change. Luckily, good climate reports were ultimately made public in the above three states, even if the reports are not currently being utilized to their full potential.

With marches, protests, international summits, and other demonstrations of support for responsible climate action happening around the world, perhaps it is only a matter of time before climate science motivates action rather than controversy.