Less Snowpack and Forests

Snowpack in the Rocky Mountains is the subject of a study in Science this week. Although snowfall was heavy this year, that is unusual in recent years. In fact, over the past thirty years, the Rockies have experienced less snowfall with shorter snowpack durations, due to higher temperatures early in the spring. NPR states that the study “attributes much of that to global warming.”

According to Scientific American:

The [snowpack] decline is "almost unprecedented" over the past 800 years, say researchers who used tree rings to reconstruct a centuries-long record of snowpack throughout the entire Rocky Mountain range.

The warming and snowpack decline are projected to worsen through the 21st century, foreshadowing more wildfires and a strain on water supplies. Runoff from winter snowpack accounts for 60 to 80 percent of the annual water supply for more than 70 million people living in the western United States.

Another study, published this month in Geology, reports that 14% of the permanent snow and ice on Mount Rainier in Washington State has melted over the past 40 years. The researchers used satellite data to view changes over the decades. You can read more in Science NOW.

Forests were the subject of many science news stories this week—wired Californian forests to track climate change (à la New Scientist), the (sad) state of “sustainable” forestry and the results of last week’s Summit of the Three Rainforest Basins (both via Nature News), a PLoS One study of forest density and climate change (see more at Scientific American) and how bacteria on moss on old-growth trees promotes general forest growth (click for study and/or press release).

There was a lot of hubbub in the science blogosphere this week about a new study in the Proceedings of the National Academy of Sciences about the origins of the human ancestor Homo erectus. The original theory held that H. erectus evolved in Africa and left for Asia, but the new paper says the opposite is true. Stone tool evidence from a western Asian site called Dmanisi predates the fossil record in Africa. It’s not certain that the tools belonged to H. erectus, as Ars Technica reports that:

the evidence of these tools is much deeper (and therefore much older) than identifiable skeletal remains, indicating that the site was occupied for at least 80,000 years, and back as far as about 1.85 million years ago.

And Nature News finds that

Even if the ancient inhabitants of the Dmanisi site were not early members of H. erectus, there is still a problem: anthropologists have previously thought that no hominins existed outside of Africa as early as 1.85 million years ago.

No wonder all the hubbub…

Finally, we mentioned ant supermodels last week and didn’t want you to miss them this week—a leaf-cutter spread in Scientific American. Enjoy!

Image by Jgrygowski/Wikimedia