The first Earth Day was held back in 1970 when 20 million Americans demonstrated for a healthy, sustainable earth environment. The Earth Day Network is a great site to check out what events are scheduled for today across the globe and what actions you can take to help make a greener planet.

Now to the stalagmite story

Researchers from the Australia National University have determined that ancient stalagmites in a submerged Italian cave indicate that there were sea level rises caused by global warming more than 200,000 years ago.

Uranium isotope dating techniques showed the stalagmites recorded water levels in the cave as far back as between 190,000 and 245,000 years ago, according to the ABC Science (Australia) article.

Lead author Dr. Andrea Dutton says the strength of the stalagmite archive is that it is not as susceptible to alteration by the environment when compared with coral reef clusters that are also commonly used to date sea water rises.

Dutton says their study shows that "the lag time between temperature change and the sea level rise may not be as long as expected".

It was previously believed that temperature rise preceded ice sheet melting by more than 3000 years.

This suggests ice sheets are capable of responding quickly to increasing temperature and CO2, and that the current melting of ice sheets may happen faster than expected, according to the report.