We drove north for two days, to arrive at a place that existed almost entirely for one reason: To facilitate the capture and, often, consumption of wild fish. The folks who run the facility make a living providing shelter, food, boats, fishing tackle, easy access to a fishing license, and they can be hired as guides. The whole point is to locate, capture, butcher, cook, and eat the fish. The fish themselves have little say in the matter.
And while talking to the people there we got a lot of advice as to how to find and capture the fish, and offers were made to assist with the butchering and culinary preparation of the piscine prey. After a bit of final preparation and a few final words of advice, we were ready to go fish hinting.
“Except for those, fish,” the woman we were talking to said, pointing towards a particularly long dock extending into the vast lake, one of the largest lakes in North America. “Don’t catch those fish.”
“Why?” I asked perplexed.
“We named them,” she said. “You can go down and look at them, the fish that hang out at the end of that dock. A couple of Northern Pike. Don’t catch those fish.”
“OK,” I said. And off we went in the other direction to catch some different fish. I figured there were about 200 million fish of a pound or more in size in this particular lake. We could skip the ones with names.
For many decades, probably for over a century, there has been an observable, measurable, increase in global surface temperature caused by human greenhouse gas pollution. For the first several decades, this increase is a clear trend, but a mild one, and there is a lot of up and down fluctuation, with periods of several years of decrease as well as increase. Then the upward trend becomes stronger, and some time around 1970 it becomes virtually relentless, going up a good amount every decade. But still, there are fluctuations in the curve.
What causes these fluctuations? Several things. The total amount of CO2, the main greenhouse gas causing this heating, has been going up during this period without stopping. Because CO2 added to the atmosphere stays there for a long time, so even if the amount released into the air by burning fossil fuels varies, there is always an upward trend. This causes the general increase, and it is why the increase in the last 50 years or so has been stronger; more CO2 has been released each year more recently.
There are large scale interactions between the ocean, which is also heating up, and the atmosphere and sea surface, the latter being what is measured in graphs of “surface temperature.” These fluctuations are decades long, and influence the degree to which the surface is warm vs very warm. There are shorter term ocean-air interactions such as La Nina (periods when the ocean is taking in more heat) and El Nino (periods when the ocean is pumping out more heat).
As the Arctic has warmed, it has been less icy, and other parts of the Northern Hemisphere have been less snowy, so there has been less sunlight reflected away, another source of fluctuation. Also, since we are talking about the Arctic, there are fewer measurements there so the traditional curves showing global warming have not included increased rates of warming there to the degree they should. Some of the fluctuations in the surface temperature curve are caused by this kind of bias, a shifting bias (because of relatively more warming in under-sampled areas) in the data set.
Humans and volcanoes make dust. Humans used to make a lot more dust before environmental regulation required that factories and power plants clean up their act. There are varying amounts of widespread low level volcanic activity and the occasional enormous eruption. This dust affects the surface temperature curve, and the dust varies quite a bit over time.
If the earth was simpler … a rocky surface, no ocean, no volcanoes, no vegetation (and thus no wildfires as well), but a similar atmosphere, changes in the amount of CO2 or other greenhouse gasses in the atmosphere would be reflected in changes in surface temperature much more smoothly. If that was the case, the amount of variation in energy supplied by the sun would probably be visible in the curve (that factor is so small compared to the other factors that it is very hard to see in the actual data). The curve on the simple earth would probably jiggle up and down a bit but there would be relatively smooth.
If you look at the temperature curve, you can see periods of greater or lesser upward change in temperature. You can even name them. I decided to do this. I chose common baby names, half male and half female, giving male names to the periods with slower increase, female names to the periods with faster increase. It looks like this:
In recent years, in what is at the root a corporate funded, and rather nefarious effort to delay addressing the most important existential issue of our time, climate change caused by human greenhouse gas pollution, science deniers have come up with their own name for one of the fluctuations in the ever increasing upward march of global surface temperatures. They call it “hiatus” (aka “pause”). The purpose of naming this part of the curve is to pretend that global warming is not real. It looks like this:
I am not impressed. And neither should you be. This is like those fish at the end of the dock. Except for the fish it is an affectation of a few people having fun, whereas with the science deniers it is a bought and paid for attempt to cause another hiatus, a hiatus in taking action to save our future.
There is a new study, the Nth in a spate of studies looking at the “Hiatus,” that asks experts on trends (economists, mainly) to look at the surface temperature trend as though it was something other than surface temperatures (they were told it was global agricultural production), to see if they identify the hiatus.
The study is by Lewandowsky, Risbey, and Oreskes, and is “The “Pause” in Global Warming: Turning a Routine Fluctuation Into A Problem For Science. It is here.
There has been much recent published research about a putative “pause” or “hiatus” in global warming. We show that there are frequent fluctuations in the rate of warming around a longer-term warming trend, and that there is no evidence that identifies the recent period as unique or particularly unusual. In confirmation, we show that the notion of a “pause” in warming is considered to be misleading in a blind expert test. Nonetheless, the most recent fluctuation about the longer-term trend has been regarded by many as an explanatory challenge that climate science must resolve. This departs from long-standing practice, insofar as scientists have long recognized that the climate fluctuates, that linear increases in CO2 do not produce linear trends in global warming, and that 15-year (or shorter) periods are not diagnostic of long-term trends. We suggest that the repetition of the “warming has paused” message by contrarians was adopted by the scientific community in its problem-solving and answer-seeking role and has led to undue focus on, and mislabeling of, a recent fluctuation. We present an alternative framing that could have avoided inadvertently reinforcing a misleading claim.
John Abraham, at the Guardian, has written it up.
The authors show that there is no unique pause in the data. They also discuss biases in the measurements themselves which suggested a slowing in warming that actually did not occur once the data were de-biased. Finally, they reported on recent work that displayed a common error when people compare climate models to measurements (climate models report surface air temperatures while observations use a mixture of air and sea surface temperatures). With this as a backdrop, the authors take a step back and ask some seemingly basic questions.
Speaking of John Abraham, he just sent me this new graphic based on the latest surface temperature measurements. This is a good moment to have a look at it:
Bad Typo in your figure
Other than that, the Pause is dead, long live the Pause..
Damn. Fixed. Thanks.
Looking at 'Emma' and 'Logan' makes me wish the NOAA and Met Office would get together and settle the differences between ERSST4 and HADSST3 from 1920-1970, in particular the wartime 1940-1946 spike.
Systematic discrepancies of up to 0.2°C over areas accounting for 70% of global temperature anomaly calculations aren't something that should be tolerated as long as they have been.
(It has little effect on the 1960-date observations and trends, I'm just venting.)
There is yet another paper showing there is no "hiatus":
Open Access, by the way.
Yes, and yet another coming out in short while, I think.
Forget that last paper that I referred you to. Tamino has just shown some disturbing errors in the paper.
" the most important existential issue of our time"
In what decade of what century do you expect us to cease to exist in consequence of a routine fluctuation in the rate of AGW?
This sort of semantic agression too much recalls what Hellen Caldicott styled her "bombing run" on the audience.
"...existential..." where Russell rhetorically bombs Greg's rhetoric by insisting on a definition that requires total and instant annihilation of Homo sapiens to fit the use of the word, thus precluding any nuance... speaking of aggression. Although perhaps 'aggression' here refers only to any conversation that falls outside the conversational parameters acceptable to the more upscale Victorian drawing rooms.
If a frog is placed in boiling water, it will perceive its existential threat and jump out. But if it is placed in cold water that is slowly heated, it will perceive semantic aggression instead and be slowly cooked to death.
At the current rate of climate forcing , it takes roughy ten generations of frogs to experience a delta T of one degree, and fifteen to forty to span the IPCC 5AR scenario range.
Calling a threat that lets frogs expire of old age 'existential ' bespeaks a rhetoric of motives.
The charge of semantic aggression stands.
Calling temperature rise the only threat that AGW brings to humanity bespeaks a rhetoric of motives itself.
The charge of unwillingness to react to threats that occur gradually stands.
Thank you for confiming the semantic agression hypothesis .
The only one calling temperature rise the only threat is ...
I was unaware you are incapable of abstract thinking... And trying to spell it all out for you is pointless as well. (Other readers will already get it.)
Keep reading this blog, though. It might start to dawn on you. As long as you stop fighting your own enlightenment. Good luck!
What is the point to set a "average temperature" for 2015 ?
2015 is not over !
May I suggest that the "average temp" will decrease through.. well... september to december ?
As most of lands are in the north emisphere and lands are much more colder than ocean (in winter), I think that having conclusions on the global average temperature of 2015 is... just... premature, pointless and unuseless. (if not an argument for the sceptics)
Toto, I'm not sure what you mean by average temperature.
Anyway, if you look at the actual march of global temperatures over the months, there is avery small effect, historically, with northern summers being very slightly warmer. But not enough to matter, it is not guaranteed, and in recent years hasn't happened at all, I think. (Have not looked at last year and this year's data). So, no, not really.
@Brainstorms, the frog-pot of water metaphor is not literally true; a frog will jump out of a pot slowly heated.
I was wondering why this data didn't line up with the other data I've seen. Then I noticed it was Greg Laden's blog, and it all became crystal clear.
Get over it, Greg. Stop drinking the Kool-aid. You were once respected as a science commentator, but the longer you keep flogging this dead horse, the less relevant you become.
Toto, temperature anomalies are measured on a month-by-month basis. The fact that 2015 hasn't ended yet only means that the sample size is slightly smaller than it will be, but doesn't mean that the coming cooler months (in the Northern Hemisphere only, mind you) will necessarily drive the average temperature anomaly downward. If October, November and December are warmer than average globally, it could even go up.
Don't demean me by calling me a denier but if we tie sea level rise to global temperature rise the sea level rose at a much greater rate starting 13000 years ago. True man has increased c02 emissions by 3% and we will get to the tipping point where there is very little sea ice but that starts the whole climate process over again.
"but if we tie sea level rise to global temperature rise the sea level rose at a much greater rate starting 13000 years ago."
Well, duh! There was much more ice to melt, and it melted over several thousands of years because the temperature rose much slower than today.
"the tipping point where there is very little sea ice but that starts the whole climate process over again"
Why would loss of sea ice cause a new ice age?
Jimbo, you are correct -- but that misses the point the well-known metaphor is intended to convey: It's an illustration of the danger brought on by an unwillingness to react to threats that occur gradually.
The data you present and analysis is statistically correct. The so called pause is erroneous. The data also reinforces what I believe to be the real debate, ie it is clear the earth has been warming since the late 1800's, but what is the cause human or something else? If you were to plot the same temperature rise vs "human activity" it would be very poorly correlated. I expect a tirade of abuse and name calling to follow - but please note I am not a denier, I have no vested interest and I am a highly qualified scientist. Sadly the question I pose is rarely covered in a balanced way. Thanks
Ian, I'm not going to call you anything, but the question you bring up has been studied exhaustively. Check out the following graph comparing natural to human causes:
(The title of the article where that graph can be found is called "A Comprehensive Review of the Causes of Global Warming", in case you want more info.) Note the years at the top of the graph. The human influence on climate change didn't begin precisely in 1956 or whatever the specific year in the IPCC report declares it to have become "dominant".
Another great resource on this was lately done by Bloomberg (and this is really cool):
Your graph of global average temp anomaly in C/100 shows 1880 at approx -30 and 1980 at approx +30 (by eye).
Please explain the 60 or so degrees C over this hundred year period that should have had all mankind jumping out of the pot.
The problem with the papers you cited and the one we are responding to is that we have a linear rate of temp increase "Emma" and "Isobel" with almost the same slope. Emma starts in late 1800's when the population was less than half of what it is today and industrial activity an order of magnitude less . If it is Human activity producing co2 which in turn causes temp increase the temp vs time graph would look nothing like the one cited above, instead it would be increasing at a faster and faster rate. I have read dozens / hundreds of articles and not once read a convincing piece of research that can connect human activity with temp change. Interestingly I have read several that argue the opposite convincingly
Not one? I think you might be reading the wrong articles, then. For starters, if you don't think GHG's affect temperature, please try to come up with a convincing explanation of how the Earth escaped the pole-to-pole glaciaton or near-glaciation of the Proterozoic snowball periods. Or, for that matter, why Venus is rather a bit warmer than Earth or even Mercury.
As far as your argument regarding human activity, the correlation between human emissions and temperature do seem quite close:
CO2 is not linearly connected to T, but logarithmic. Therefore, Ian's objection does not hold. Rebuttal done, "highly qualified scientist" Ian will now read up on basic climate change, in particular forcings. Right, Ian?