Has Global Warming Stopped?
Has global warming stopped? There's been much discussion of this lately, and in particular in the context of a fairly quiet Sun that we have seen of late - sunspot activity has been limited for a relatively extended period. So what do the temperature measurements say?
There are 4 main world temperature indexes that track global temperatures - two using land and sea-based (surface) temperatures and two using satellite and balloon measures. The land based measures show higher temperatures than the satellite based measures. Astonishingly, the index maintained by global-warming alarmist James Hanson (NASA GISS) shows the highest temperatures, while that maintained by warming-skeptics Roy Spencer and John Christy (UAH-MSU) shows the lowest temperatures and flattest trend. Intermediate are the RSS-MSU satellite measures and the Hadley Centers HadCRUT surface-temperature index. Here are how the four measures trend since 1979 (based on least squares regression of monthly anomalies), when the satellite measures began:
All measures show a clear warming trend over the last 28+ years, though clearly the satellite measures show less extreme warming. So let's look at the less extreme surface temperature measure (the Hadley Center's index) to see how the temperatures look beginning in 2001:
As we can see, while the overall temperature trend is positive, there is a clear negative trend over the past 7+ years. So global warming has clearly taken a break, no?
Well, maybe not. Let's divide the temperature record into 4 evenly spaced periods of 7+ years, and see what the Hadley Center data tells us.
Well, look at that. Over the last 28 years, 3 out of 4 seven-year periods show no warming - two of them slope negative and one is flat. Out of a 28-year stretch, only one seven year period shows a positive temperature trend! Yet the overall trend is quite clearly positive. The record looks like an ever-ratcheting up temperature trend with multi-year periods of non-growth. The best guess, looking at this graph, is that we can expect another big temperature bump-up fairly soon.
Now perhaps this is really it - maybe the warming is all over. Maybe the quiet sun will send temperatures plummeting - though we have a long way to go if that's the case - temperatures are still above the mean of the last 28 years.
While few things in this world (other than my own personal enrichment) would give me more pleasure (for a number of reasons) than clear evidence that global warming doesn't exist, I fear there's little reason for such optimism. The insufferable scolds will not be going away, nor can we blissfully ignore the effects of burning fossil fuels - we'd need to see a number of more years of this kind of data before this controversy can be put to bed.
Data sources:
NASA GISS
HADCrut
RSS-MSU
UAH-MSU
There are 4 main world temperature indexes that track global temperatures - two using land and sea-based (surface) temperatures and two using satellite and balloon measures. The land based measures show higher temperatures than the satellite based measures. Astonishingly, the index maintained by global-warming alarmist James Hanson (NASA GISS) shows the highest temperatures, while that maintained by warming-skeptics Roy Spencer and John Christy (UAH-MSU) shows the lowest temperatures and flattest trend. Intermediate are the RSS-MSU satellite measures and the Hadley Centers HadCRUT surface-temperature index. Here are how the four measures trend since 1979 (based on least squares regression of monthly anomalies), when the satellite measures began:
All measures show a clear warming trend over the last 28+ years, though clearly the satellite measures show less extreme warming. So let's look at the less extreme surface temperature measure (the Hadley Center's index) to see how the temperatures look beginning in 2001:
As we can see, while the overall temperature trend is positive, there is a clear negative trend over the past 7+ years. So global warming has clearly taken a break, no?
Well, maybe not. Let's divide the temperature record into 4 evenly spaced periods of 7+ years, and see what the Hadley Center data tells us.
Well, look at that. Over the last 28 years, 3 out of 4 seven-year periods show no warming - two of them slope negative and one is flat. Out of a 28-year stretch, only one seven year period shows a positive temperature trend! Yet the overall trend is quite clearly positive. The record looks like an ever-ratcheting up temperature trend with multi-year periods of non-growth. The best guess, looking at this graph, is that we can expect another big temperature bump-up fairly soon.
Now perhaps this is really it - maybe the warming is all over. Maybe the quiet sun will send temperatures plummeting - though we have a long way to go if that's the case - temperatures are still above the mean of the last 28 years.
While few things in this world (other than my own personal enrichment) would give me more pleasure (for a number of reasons) than clear evidence that global warming doesn't exist, I fear there's little reason for such optimism. The insufferable scolds will not be going away, nor can we blissfully ignore the effects of burning fossil fuels - we'd need to see a number of more years of this kind of data before this controversy can be put to bed.
Data sources:
NASA GISS
HADCrut
RSS-MSU
UAH-MSU
posted by ziel | 6/24/2008 10:36:00 PM
6 Comments:
Human activity has nothing to do with global warming or cooling. The earth haa had ice ages and warm periods since forever, no SUVs needed.
That could be, and that would be nice. But it's hard for me to come to that conclusion - I have to defer to general consensus of the experts on this one, that human activity contributes to increasing temperatures.
We have increased CO2 in the atmosphere from 315 parts per million in roughly 1960 to 385 parts per million.
The thing is, that from 1940-1960 the world was cooling, so much so that Ehrlich the butterfly expert was writing about the impending ice age and the mass starvation that would follow in the early seventies. We had alot of cars that burned much dirtier in 1960, so why was it still getting colder.
Basically car exhaust is just CO2 and oxygen now because they have filtered so much out of it. There is not a great concentration of other gunk therein compared to these two. CO2 is something that every animal and man breathes out and plant life breathes in. Plants would die without it. Many consider our higher crop yields due to the extra CO2, but I digress.
Methane is a much more potent greenhouse gas than carbon is. If you want to fight global warming, limit yourself to red meat only once a week. A big cow's 24/7 flatulence would outdo your car's during your commute----just think, all that vegetarian grass in those five stomachs------worse than draft beer.
Im all for hybrids, plug-in hybrids, hydrogen cars, Craig Venter bugs that eat waste and shit petroleum (can you believe he's bred bugs that can do this----the same guy that mapped the human genome---incredible), ethanol from switchgrass cars, and flying carpets.
But more than anything, Im just mean, and hope we have 20 very cool years of tempratures about five full degrees below normal with snowy winters just to make Al Gore look like the pompous pretentious-faux-holier-than-thou-jackass he is. I hope Noo Yawk and LA in particular (and Seattle too) get really hit hard. Londong too. I mean tons of snow, and summers so cool that its unpleasant to go to the beach. I want the same people who fearmonger about global warming to practically beg God for it because its too cool to get in the pool in the summertime and the endless grey falls and winters make them depressed. But Ziel probably is right, and it will re-warm soon, giving the Marxist-in-eco-garb-types more cannon fodder to primp their egos and spread Malthusianism and communalism to the first world. But I can hope for their frostbitten toes to fall off and will do so anyway.
Yes, perhaps this is just a 30-year warming phase we're in, and it will get cooler again. But the 'lack of warming' over the last 7 years is no evidence that this is the case.
So for years you've maintained that global warming was all hooey.
What was it that caused this 180 - the avalanche of "evidence" to the contrary? personal pride eventually gave way?
I have NOT maintained that global warming is 'all hooey.' I have - and still believe - that much of the reactions to it are nonsense - for example, the just release national security assessment. Also, things like banning incandescent bulbs, standby-mode on electronics, the assumptions about very specific regional impacts such as longer droughts here and more floods there. And of course the increased hurricane predictions, which the preponderance of evidence indicates is false. But I have always accepted that we have been in a pronounced warming period, and that increased CO2 is a likely culprit, and that we should begin to explore new technologies - dramatically new technologies - as the only way to avoid very negative effects 100 years from now.
And I still thing James Hansen is kook.
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