The Petermann Glacier is a vast tongue of flowing ice in Greenland. In 2010 it calved - broke off a chunk - releasing an iceberg far larger than Manhattan Island in New York City. That huge chunk of ice moved into the ocean and eventually melted in the Atlantic (see Related Posts below for more on that event).
And now Petermann has done it again. A crack appeared several years ago, and on July 16th conditions were right to allow a new chunk to break free:
Note the scale: the width of that glacier at that point is 20 kilometers, or 12 miles. This iceberg was imaged by NASA's Aqua satellite, designed to monitor Earth's oceans. The berg itself is about half the size of the last one, but don't kid yourself: that's still huge.
As before, we can speculate whether this is due to global warming or not. Icebergs calf all the time. However, note that the last time, the berg calved later in the summer (August), and this crack is much farther up the glacier than usually seen.
As climate scientist Michael Mann says, global warming is like loaded dice. You don't know if any particular throw of snake eyes is due to them being fixed, but you'll see a lot more rolls turn up snake eyes than you would otherwise. Global warming is predicted to give us longer, hotter summers, drier conditions across the US, more record temperatures, thinner arctic ice, and having it cover less surface area of the Earth. And, yes, more frequent glacier calving.
By the way, the 2010 calving event was the largest seen in nearly 50 years. And also by the way, June 2012 was one of the hottest since records have been kept. And also also by the way June 2012 had the highest land and ocean average surface temperatures in the northern hemisphere in recorded history. And oh, one more thing: it also was the 328th consecutive month with a global temperature higher than the 20th century average. You can read all about this in the NOAA report "State of the Climate Global Analysis" for June 2012.
But you global warming deniers, you just go ahead and keep on denying. Keep cherry picking, keep changing the subject, keep misinterpreting graphs, and keep slinging ad hominems (note: that last one is skeevy and foul and disgusting almost beyond belief).
In the meantime those of us who understand the actual situation will take it seriously, and continue to speak out. Because this we know:
The Earth is warming up. The rate of warming has increased in the past century or so. This corresponds to the time of the Industrial Revolution, when we started dumping greenhouse gases into the atmosphere. Greenhouse gases warm the planet (hence the name) -- if they didn't we'd have an average temperature below the freezing point of water. Carbon dioxide is a greenhouse gas which is dumped into the atmosphere by humans to the tune of 30 billion tons per year, 100 times the amount from volcanoes. And finally, approximately 97% of climatologists who actually study climate agree that global warming is real, and caused by humans.
NASA Earth Observatory image by Jesse Allen, using data from the Land Atmosphere Near real-time Capability for EOS (LANCE).