A pair of new studies drive a stake through the heart of the claims of global warming skeptics who believe that the earth's rapidly-warming temperatures are part of some natural phenomenon.

It's true that the climate is always changing.  And skeptics like to point to the Medieval Warm Period of the years 800 to 1200 or the Little Ice Age, a period of cooling that spanned from roughly 1300 to 1850, to cast doubt on the overwhelming scientific consensus that man's industrial activity and fossil fuel burning is the cause today's warmer.

But the research proves the rise in global temperatures over the past 150 years has been far more rapid and widespread than any warming period in the past 2,000 years.

One of the studies is published in the journal Nature; it shows the Little Ice Age and other natural fluctuations affected only limited regions of the planet at a time.  Today's global warming crisis is just that, global - and it's the first and only planetary warming period in the past 2,000 years. 

The other study appears in Nature Geoscience, shows that the warming periods of the past weren't anywhere near as dramatic as the rapid temperature swings occurring since the dawn of the industrial era.