Study Shows How Water Could Have Flowed on 'Cold and Icy' Ancient Mars

For scientists trying to understand what ancient Mars might have been like, the red planet sends some mixed signals. Water-carved valleys and lakebeds leave little doubt that water once flowed on the surface. But climate models for early Mars suggest average temperatures around the globe stayed well below freezing.

Simulation shows the high cost of dementia, especially for families

A new simulation of how the costs and the course of the dementia epidemic affect U.S. families finds that neurodegenerative conditions can more than double the health care expenditures of aging and that the vast majority of that financial burden remains with families rather than government insurance programs.

Climate models may underestimate future warming on tropical mountains

In few places are the effects of climate change more pronounced than on tropical peaks like Mount Kilimanjaro and Mount Kenya, where centuries-old glaciers have all but melted completely away. Now, new research suggests that future warming on these peaks could be even greater than climate models currently predict.Researchers led by a Brown University geologist reconstructed temperatures over the past 25,000 years on Mount Kenya, Africa’s second-highest peak after Kilimanjaro. The work shows that as the world began rapidly warming from the last ice age around 18,000 years ago, mean annual temperatures high on the mountain increased much more quickly than in surrounding areas closer to sea level. At an elevation of 10,000 feet, mean annual temperature rose 5.5 degrees Celsius from the ice age to the pre-industrial period, the study found, compared to warming of only about 2 degrees at sea level during the same period.

Study suggests impact of climate change on agriculture may be underestimated

Studies of how climate change might affect agriculture generally look only at crop yields — the amount of product harvested from a given unit of land. But climate change may also influence how much land people choose to farm and the number of crops they plant each growing season. A new study takes all of these variables into account, and suggests researchers may be underestimating the total effect of climate change on the world’s food supply.

Tiny chameleons deliver powerful tongue-lashings

A new study reports one of the most explosive movements in the animal kingdom: the mighty tongue acceleration of a chameleon just a couple of inches long. The research illustrates that to observe some of nature’s best performances, scientists sometimes have to look at its littlest species.

Connecting Elevation and Evolution

About 34 million years ago, global temperatures took a dive, causing a sudden wave of extinctions among European mammals. In North America, however, life went on largely unscathed. A new study explains why: The rise of the Rocky Mountains had forced North American mammals to adapt to a colder, drier world.

Researchers Track Ammonium Source in Open Ocean

To understand the extent to which human activities are polluting Earth’s atmosphere and oceans, it’s important to distinguish human-made pollutants from compounds that occur naturally. A recent study co-authored by a Brown University professor does just that for ammonium, a compound that is produced by human activities like agriculture, as well as by natural processes that occur in the ocean. The research, based on two years of rainwater samples taken in Bermuda, suggests that ammonium deposited over the open ocean comes almost entirely from natural marine sources, not from anthropogenic sources.