Climate change update

Posted at 4:36 PM on January 16, 2009 by Paul Huttner (2 Comments)

Climate change forcing graph shows the impacts of various elements on global temperature. Courtesy of Dr. Kerry Emanuel MIT.

We hit -21 in the Twin Cities this week for the coldest temperature in 5 years. So the whole "global warming" thing is over right?

Not exactly. I wish I had a dollar for every time somebody says something about climate change that either refers to WEATHER or misstates the science of climate change.

At the risk of starting a few fires on a cold January day in Minnesota, let's bust a few myths about climate change right here.

1) We will still have winter. Sometimes it will even be really, really cold.

2) We will still have "below average" years. In fact for those who say we are now "cooling" let's remember that we have had the 10 warmest years on record since 1997. During that stretch we would have expected 6 above average and 6 below average years statistically speaking. Do you have any idea what the odds are of having the 10 warmest years on record, in one decade?

3) 2008 was above average globally. In fact it was the 10th warmest year on record. Just because it was slightly cooler than in previous years does not mean we are in an overall long term cooling trend. What is really surprising is that we have not had a below average year globally in over a decade.

4) Variations in our sun and solar output have been factored in to climate change models. The graph above (sorry for the quality) shows how greenhouses gasses have much greater climate forcing than volcanic, solar or other variables.

5) Urban heat island effects are accounted for, and though a few stations may be marginally effected by their location they are such a small part of the record as to be insignificant. The vast majority of data on climate change comes from ice cores, tree rings, deep lake sediments and other sources independent of our surface based temperature network.

6) CO2 has always varied naturally, but the rate of increase in the past 50-100 years is far higher than at any time in the past. That's the human "fingerprint" on global atmospheric changes.

There really is no debate that the planet is getting dramatically warmer. The real questions are; what are the specific and regional effects going to be? How will we adapt to climate change? What policies for reducing greenhouse gasses make scientific and economic sense? Will we be good stewards of our planet and environment?

We will talk plenty more about climate change in the coming months and years. For right now if you really want to spend some quality time learning what the best science in the world says about climate change, spend a quality weekend reading through parts of the IPCC report.

Enjoy the milder temperatures as we emerge from the deep freeze!

PH

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Comments (2)

1. Agreed
2&3. Yes but the trend has been negative for ~7-9 years, when you start from a high point (1998) of course temps will be above average (for a while) even if you are cooling. 7-9 years qualifies as a long enough trend, when you are concerned about warming over 30-40 years (~1960-2000). Many other model charts show huge divergence from reality the last 10 years; I assume the one you show has been "improved" recently.
4. Factored in yes, but correctly? Nobody knows.
5. Accounted for, but correctly? And keep in mind McIntyre's audit showing most stations do not meet specs
6. Not sure that is true, but does it matter? That is the human fingerprint on CO2 levels (maybe).
There is no debate that earth has been getting warmer since the last ice age. There is much debate whether CO2 is a significant factor.

Posted by BFJ | January 16, 2009 11:36 PM

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Thanks BJF:

Yes we have been getting "cooler" in the past few years since 1998, which was the warmest year in 1000 years. (Malcon Hughes Univerisity of Arizona etc.) Still, ALL of those years have been well above the 20th century mean globally, and most have been top 10 warmest years on record. NONE have been below average.

I for one would like to see at least one (maybe 2009?) and preferably at least half of the next 10 years below the 20th century mean global temperature before I declare there is a global cooling trend. I am open to whatever evidence presents, if that happens. We would expect to see half of the next decade below the 20th century mean statistically. Anything above that continues the warm pattern.

By the way, I think it's interesting that lately (PRAVDA of all sources!!) people are using Milankovitch Cycles as evidence we are headed toward a new ice age. This is nothing new, we've known about these solar cycles for a long time. The next ice age may not start for 50,000 years or more. A critical question is, will greenhouse gasses force the climate significantly warmer in the next few centuries?

I also find the current solar minimum interesting. Assuming sunspots and solar output increase in the next few years and peak around 2012 or 2013, will that add to what has been a very warm decade? Is the fact that we have "cooled" recently but remain above average globally a reflection of solar minimum in an era of overall climate warming?

As I have said before, I am a synoptic and broadcast meteorologist and not a climate expert. I do not know all the answers and certainly the science of climate change is still evolving.

I just think this is the most fascinating discussion there is on the planet today.

Thanks for your comments!

PH

Posted by Paul Huttner | January 17, 2009 2:31 PM

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