Climate Climate & Energy

‘The hockey stick is broken’–Well, no … but who’s playing hockey anyway?

(Part of the How to Talk to a Global Warming Skeptic guide)

Objection: The Hockey Stick graph -- the foundation of global warming theory -- has been shown to be scientifically invalid, perhaps even a fraud.

Answer: The first order of business here is to correct the mischaracterization of this single paleoclimate study as the "foundation" of global warming theory.

What's going on today is understood via study of today's data and today's best scientific theories. Reconstructions of past temperatures are about, well, the past. Study of the past can be informative for scientists, but it is not explanatory of the present nor is it predictive of the future. The scientific foundation of global warming theory contains much more than a few tree-rings and the temperature during the Medieval Warm Period.

RealClimate has an interesting article about what it would mean for today's climate theories if the MWP had indeed been warmer than today.

Now, about that pesky bit of sporting equipment ...

Yes, the last ice age started thawing over 20,000 years ago, but that stopped a long time ago

(Part of the How to Talk to a Global Warming Skeptic guide)

Objection: Global warming has been going on for the last 20,000 years.

Answer: It is true that 20,000 years ago the temperature was some 8 to 10° C colder than it is today. But to draw a line from that point to today and say, "look, 20K years of global warming!" is dubious and arbitrary at best.

If you have look at this graph of temperature, starting at a point when we were finishing the climb out of deep glaciation, you can clearly see that rapid warming ceased around 10,000 years ago (rapid relative to natural fluctuations, but not compared to the warming today, which is an order of magnitude faster). After a final little lift 8,000 years ago, temperature trended downward for the entire period of the Holocene. So the post-industrial revolution warming is the reversal of a many-thousand-year trend.

‘Greenland used to be green’–Don’t judge a book by its cover, much less a land by its name

(Part of the How to Talk to a Global Warming Skeptic guide)

Objection: When the Vikings settled it, Greenland was a lovely, hospitable island, not the frozen wasteland it is today. It was not until the Little Ice Age that it got so cold they abandoned it.

Answer: First, Greenland is part of a single region. It can not be necessarily taken to represent a global climate shift. See the post on the Medieval Warm Period for a global perspective on this time period. Briefly, the available proxy evidence indicates that global warmth during this period was not particularly pronounced, though some regions may have experienced greater warming than others.

Second, a quick reality check shows that Greenland's ice cap is hundreds of thousands of years old and covers over 80% of the island. The vast majority of land not under the ice sheet is rock and permafrost in the far north. How different could it have been just 1,000 years ago?

Below is a brief account of the Viking settlement, based on Jared Diamond's "Collapse".

How a grassroots biodiesel group can show the way for others

The way that Rob Del Bueno backed into the world of biofuel almost by accident, as told in the article “Small Potatoes,” is emblematic of the way most folks get engaged in grassroots biofuel development. It starts with a desire to use a renewable fuel to power your life long before a GMO-happy megacorporation was […]

The top 10 reasons to give a hoot about biofuels

Well, here we are, at the end of Grist’s illustrious series on biofuels. We’ve thrown a lot of information at you, and we hope it’s becoming clear why biofuel production is a big, Relevant Thing that deserves your attention. But just in case you need more proof, behold: Grist’s Top 10 Reasons To Give a […]

Unusual Weather We’re Having, Ain’t It?

Number-crunchers say 2006 on track to be the sixth-hottest on record As 2006 limps to a close, it’s measuring in as the world’s sixth-hottest year on record. It’s the warmest Britain has seen since wenches were hoisting tankards of grog (er, since records began in 1659), and the third-warmest in the U.S.’s Lower 48 since […]

‘The Medieval Warm Period was just as warm as today’–Repeating this point does not make it true

(Part of the How to Talk to a Global Warming Skeptic guide)

Objection: It was just as warm in the Medieval Warm Period (MWP) as it is today. In fact, Greenland was green and they were growing grapes in England!

Answer: There is no good evidence that the MWP was a globally warm period comparable to today. Regionally, there may have been places that exhibited notable warmth -- Europe, for example -- but all global proxy reconstructions agree it is warmer now, and the temperature is rising faster now, than at any time in the last one or even two thousand years.

‘It was warmer during the Holocene Climatic Optimum’–This period was not global and not like today

(Part of the How to Talk to a Global Warming Skeptic guide)

Objection: It was warmer during the Holocene Climatic Optimum than it is today -- without any human influence.

Answer: Though some temperatures during that period were in the same range as today, they were confined to the northern hemisphere and the summer months.

The strangest biofuel sources you’ve never heard of

Sure, you’ve heard of corn and switchgrass as potential sources of biofuel. But those are rendered totally boring in light of the potential of trash, dead cats, and human fat to meet our energy needs. Make your engine purr. Photo: iStockphoto Surprising sources abound in the world of biofuels, with researchers probing the farthest reaches […]

What Brazil can teach the U.S. about energy and ethanol

In 2006, Brazil officially achieved “energy independence” — that is, its oil exports came into line with imports and cancelled them out. No longer beholden to foreign suppliers for its energy needs, the nation theoretically has no stake in costly Middle East military adventures to secure access to oil reserves. Grain alcohol? Haven’t touched the […]