April 28, 2010
For most of the 2.5 million years that humans and their predecessors have been around, the Earth has been a volatile place. Subtle shifts in the planet’s orbit have triggered large temperature swings; glaciers have marched across North America and Europe and then retreated. But, about 10,000 years ago, something unusual happened: The Earth’s climate settled into a relatively stable state, global temperatures started hovering within a narrow band, and sea levels stopped rising and falling so drastically.
How Worrisome Is Ocean Acidification?
February 18, 2010
Global warming tends to receive the bulk of attention these days, but it's worth remembering that hotter temperatures aren't the only consequence of putting more carbon-dioxide into the air. As the oceans keep absorbing more CO2, the chemistry of seawater is changing at a fairly rapid clip—steadily becoming more acidic. Some of the effects of ocean acidification are fairly well understood. Species that rely on calcium carbonate to make their skeletons, such as coral or some types of shellfish, will find it much harder to build their shells as the ocean becomes more acidic.