Issues - (Man-Made) Climate Change Advocates

(CNN) -- They say they've discovered two openings that could channel warm seawater to the base of the huge Totten Glacier and bring the threat of potentially disastrous melting. The glacier is bigger and thinning faster than all the others in East Antarctica.

It contains enough ice to raise the global sea level by at least 11 feet (3.4 meters), according to researchers from the University of Texas at Austin who were among the authors of a new study published this week in the journal Nature Geoscience.

"While the Totten melt may take several centuries, once change has begun our analysis reveals it would likely be irreversible," Greenbaum said in comments cited by the Australian Antarctic Division.

(CNN) -- Meteorologist Tom Sater explains why the stakes are higher than ever in 2015 for climate change and global warming.

For the first time since we began tracking carbon dioxide in the global atmosphere, the monthly global average concentration of this greenhouse gas surpassed 400 parts per million in March 2015, according to NOAA's latest results.

It was only a matter of time that we would average 400 parts per million globally,” said Pieter Tans, lead scientist of NOAA's Global Greenhouse Gas Reference Network.

“This marks the fact that humans burning fossil fuels have caused global carbon dioxide concentrations to rise more than 120 parts per million since pre-industrial times,” added Tans. “Half of that rise has occurred since 1980.”

(CNN) -- March 2015 was the warmest March since record-keeping began in 1880, says the National Oceanic and Atmospheric Administration. And the first quarter of 2015 was the warmest first quarter on record in those same 136 years.

The uninterrupted continuation of the warming trend is no surprise. The 10 warmest years on record have occurred in the past 17 years.

And though the rise in the last 10 years has been gentle by comparison, since 1910, the clear trend has been up, according to NASA's Global Land-Ocean Temperature Index.

In the latter two thirds of that time, warming and the effects on climate have been epochal, says the Intergovernmental Panel on Climate Change. "Since the 1950s, many of the observed changes are unprecedented over decades to millennia."

March 2015 edged past the last record high March, which was in 2010, rising by 0.09 degrees Fahrenheit (0.05 C). Average global land and water temperatures for the first quarter of this year beat the last record first quarter, 2002, by the same margin.

Yet another broken record this March was more obvious to the eye. The expanse of Arctic sea ice shrunk to an absolute low for any March on record.

"The average Arctic sea ice extent for March was 430,000 square miles (7.2 percent) below the 1981--2010 average. This was the smallest March extent since records began in 1979," NOAA said.

On the other end of the globe -- in the Antarctic -- sea ice has been on the gain, and this year, it hit a record March high.

But globally, the overall result is a big net loss. "The upward trend in the Antarctic ... is only about a third of the magnitude of the rapid loss of sea ice in the Arctic Ocean," according to NASA.

If carbon emissions continue on course, further temperature rises should bring decades-long megadroughts to the western half of the United States in this century.

This March saw the highest level of greenhouse gases in Earth's atmosphere since record keeping began. Not the highest level for any March but the highest level ever at 400 parts per million, NOAA says.

The current severe drought that has decimated California's water supply has lasted about three years. The drought that turned much of the U.S. West into the Dust Bowl in the 1930s lasted 10 years.

[CNN] The study predicts that what remains of the once prominent ice shelf, a thick floating platform of ice, and will most likely to vanish before the end of this decade Ice shelves are extensions of glaciers and function as barriers. Their disappearance means the potential acceleration of glaciers diminishing as well, increasing the pace of global sea level rise.

Larsen A disintegrated in January 1995. Larsen C has been somewhat stable with some evidence of thinning and melting, the space agency said after observing satellite imagery in 2012.