The yearly temperature anomaly for the last 150 years from two sources: US National Climate Data Center and UK Climate Research Unit. Courtesy of NOAA
There is no dispute among knowledgeable and unbiased scientists that climate change is occurring.
Why, then, is there still ambivalence on the part of the public about how to respond?
Partly it’s because there are powerful vested interests determined to obfuscate the obvious; partly it’s because it can be difficult to sort out fact from fiction.
Debates tend to devolve into a shouting match between the extremes of the political and economic spectrum. Science can get lost in the cacophony.
Here’s what comes out when the subject of global warming/climate change is broken apart and simplified.
Just The Facts, Ma’m
The long and short of it is that the temperature of the atmosphere is a degree (F) warmer than it was a hundred years ago, and the ocean is a foot higher.
Burning coal, oil, and natural gas — fossil fuels — releases carbon dioxide.
Models of the atmosphere which incorporate increasing amounts of carbon dioxide predict precisely the results we observe: Higher temeperatures on a global average, greater persistence of weather patterns, (Remember the Omega Block that wouldn’t leave?) and more weather extremes such as unseasonable cold snaps this September.
The convergence of theory and observation leaves virtually every impartial earth scientist convinced of the reality of climate change caused primarily by the burning of fossil fuels.
Atmospheric carbon dioxide record for the last 400,000 years, courtesy of NASA
Look Over There!
Powerful corporations, which have an interest in continuing quarter-to-quarter profits regardless of the consequences, have used disingenuous and downright dishonest tactics to obscure the clear harm that their activities are doing to the planet.
Statistics can be used to show virtually anything, and in this case it is easy to muddy the clear waters of truth.
The Scale Of Climate Change
The earth has, at times in the past, been both colder and warmer than it is today.
This fact is used by climate-change deniers to argue that the recent temperature changes are a result of natural cycles. Unfortunately, this is an inaccurate comparison, as natural climate cycles take tens of thousands of years at the least.
The recent change in temperature of the atmosphere-ocean system is unprecedented. In a thousand years, the temperature will rise ten degrees at the current rate of increase (which itself has been increasing). Such an increase has never happened in less than ten thousand years.
Climate Change: Here’s An Example Of The Misuse Of Statistics
Suppose you have a theory that because of the orbit and inclination of the earth relative to the equatorial plane, the temperature will rise during the spring in the northern hemisphere. Now let’s look at the observations. Every year the temperature rises between the beginning of April and the end of the month.
Now suppose someone wants to make the case that the temperature actually falls in April. He can point to the temperature record for almost any day between 8 p.m. and 5 a.m. During the night, the temperature almost always falls. The same kind of chicanery is going on with the citing of temperature records by those who disagree with the theory of manmade climate change.
1998 was an exceptionally warm year. In fact, it was the warmest year on record (2014 is on track to surpass it) due to a very powerful El Niño. Interestingly, those who disagree with the climate change theory seem to inevitably start their measurement of temperature change with 1998. That way, whatever period of time they use, the temperature appears to be falling.
In fact, a properly smoothed temperature graph from the start of the industrial revolution to the present shows an unabated rise, just as a properly smoothed record of April temperatures shows a steady rise.
Short Term Fluctuations In The Earth-Atmosphere System
Temperatures fluctuate. There are well-defined periods, such as daily or yearly; and there are less certain ones, such as El Niño-Southern Oscillation (ENSO). As long as nay-sayers can pick their spots and start their temperature record where they choose, or truncate it wherever they like, there will be data presented that paints a distorted picture of the temperature trend over the most recent century.
The Future of The Climate
Maybe all the scientists are wrong. It’s not likely, but it has happened before. Nevertheless, there is grave danger in ignoring what the climate is telling us.
The fact is that the general circulation of the atmosphere is not well understood. What we do know is that the climate has been very different in the past. Of its own accord, the climate would indeed change very substantially — but over many millennia. Humanity has now begun a process that is without precedent in climatic history, and which could spiral out of control in a short time.
Oh, I meant to add… On the topic of fuels, which fuel do you think releases the most CO2 to the atmosphere for the quantity of heat produced? You might not believe the answer. So check my data: http://www.quirkyscience.com/maximize-carbon-dioxide-greenhouse-gas-production/
And as for non-fuel additions, the Smithsonian magazine wrote on the topic of “green cement” and its contribution of approximately 5% of the whole world’s CO2. It sounds wrong at first, but if you check out the chemistry, you’ll realize it makes sense: http://www.quirkyscience.com/cement-production-aggravates-carbon-dioxide-levels/
If you really want to compare calm presentation of the facts with silly outbursts of nonsense, just view the comments written before this one. It becomes obvious what is said about obfuscation is true.
Yes climate change is always occurring but major changes have occurred over short time spans. It’s not only millenia. What about the Medieval Warm Period? C02 certainly wasn’t to blame then. Oh yes and there’s always mention of decreasing arctic ice. Where’s the mention of the increasing antarctic ice? As for statistics being selectively chosen by deniers, so it with the extremists. In fact the “climate-gate” emails clearly show attempts at suppressing the release of data or the methods involved so that true scientific inquiry is compromised.
So much is still unknown about overall climate dynamics. Pinning so much on CO2 sounds good, but it doesn’t work. When all existing models fail to predict the lack of global temperature rise for almost 20 years now, in the face of rising CO2 levels something is wrong. Allowing the rigors of open-minded and true scientific inquiry to proceed is what is needed. It ain’t happening enough right now.
I don’t think it’s true that there is no dispute among scientists that “man made” global warming is occurring. My geology texts show that for 12k yrs we have been emerging from an Ice Age” (the 4th in the last 1mm yrs) & that we are not much more than half way into the next 300k yr inter-glacial period. Earth has only lost a little more tan a 1/2 of its’ anticipated glacial loss. It has been assumed for some time that the total loss will have significant effects on earth’s climate and ocean levels and that this will occur regardless of human activities. I don’t believe that geologists and archaeologists agree that we are responsible for global warming.. Perhaps there is consensus among meteorologists but that consensus is limited this scuence.
you are kidding really! wake up this has been happening for billions <—-(laughing) of years
This explanation is so clear and simple I wish teachers would distribute it in schools. It’s the politicians that need the explanation, though!
Frank, I have mentioned how greenhouse gases affect the atmosphere several times: CO2 and methane are transparent to solar radiation, but opaque to the earth’s microwave radiation. The heat gets let in but not out. If Victoria commands that that be stated in 500 words or more, it will be done.
An easy-to-read and well reasoned article. It is the last sentence which I find most alarming.
The only alarming aspect is that he makes this claim using 150 years of data. May as well describe the moon using one inch of topography for evidence.
All this is true, to the fact that statistics can be bent ANY way. Why start at 1850 ‘the beginning of the industrial revolution’. That’s the same as using 1998 as a comparison since, as data shows, the Little Ice Age ran from around 1300-1850. See http://en.wikipedia.org/wiki/Little_Ice_Age. Interesting to peg the graphs starting at 1850?
Climate changes, all the time, over time. Many factors affect climate. The problem is the impact of those factors. Solar variations have a much more profound affect than any man/human affect. Similarly, local volcanic activity (ie Mt Pinatubo in the 1980s) can have widespread global impact, even if for a short period, that completely counteract against ‘150 years of man-made global warming’.
A simple question: IF you eliminated ALL human activity from the planet, just what WOULD be the climate?
Ice age? The Earth has been warming since the last one.
Good to see the phenomenon explained in such simple terms, Jon. But then, that;s what we have come to expect from Decoded! I would like to see a follow up article explaining the mechanism (the way CO2 and other hydro-carbon gases provide an insulating blanket to reduce heat loss over night and in winter and the thicker blanket that has developed over the last 100 years has proved to be too much of a good thing – like using a winter weight quilt in summer!)
Well, Dave, consider the time scales. You can start with 1850, 1900, 1950. The temperature goes up and the CO2 goes up — both at unprecedented rates. As for your last question, we know for sure that there would be no city heat islands; there would be no narrowing of day/night temperature range because of contrails. If you are suggesting that burning fossil fuels has had no effect on the climate, I think you’re, as they say, spitting into the wind.