If one looks at the data, all of it, on the question of climate change in the present, an overwhelming point becomes obvious: while there are natural cycles to temperature and climate, some quite significant, in the present, human activity is creating climate change through the emissions of green house gases. While everything in science is provisional and should be read with skepticism, the accumulation of evidence on this point is sufficiently large that it should be treated as the default position. So why is it, in the last year, the public consensus for AGW has collapsed? There are three reasons: the first is that the previous decade had not only the long term build up of green house gases, but several more cyclical factors increasing the rate of air temperature rising, while now several are working against air temperature increases. The second is that there is a highly organized anti-climate change lobby, well funded, but also backed by a social network which systematically denies a host of other "evidence based" understandings of reality. The third is that there are localized factors which contribute to the sense, for those who wish to believe it, that the climate crisis has passed. One of these is the way that the climatologists behaves when attacked: it is arrogant, dishonest, vicious, and narrow minded, and this behavior is used as proxy, often by even more narrow minded, vicious, and dishonest people, to disprove the large accumulation of data.

In short, scientific judgments play the cards, and politics plays the people. The cards say the atmosphere is increasing in heat content, and that increase is driven by human activity. The people say that they don't want to pay for something, and are willing to hide in any scrap of doubt. Climatologists are people, and like many people under attack, they circle the wagons. Since, in most areas of human activity, circling the wagons is a sign of dishonesty or failure, this is used to raise doubt. But let's look at the cards, and see why the denialists are stealing the pots.

Recently I had a reason to look at tree rings. I am presently trying to both date accurate the Bronze age cooling period (roughly 2200 BCE - 2000 BCE) and relate it to historical events. This is because the response of human culture to the cooling period is an important mirror for our own age. Because of the intricacies of dating, nothing that we have as "history" that far back can be dated with a precision of more than 150 years to either side. The dates that are listed in books are based on a relatively few markers, and texts which might or might not be accurate, artifacts which may, or may not, have been left undisturbed. How one reads a historical text then is provisional, because tomorrow it might be moved 30, 50, or 100, years relative to an absolute calendar. This is one reason why history and archeology often focus on interiority, because we have a better guess of what followed what, rather than an absolute when.

To date the cooling period means looking at the history of climate, and that means, largely, ice cores and tree rings, because these offer the most clearly time delineated view of our history. Both have their caveats and problems. For example, in some cases wider tree rings mean a warmer period, but not for some trees in some locations, where ordinarily tree growth is slowed by a hot, dry, summer period. In these cases a wide ring means a cooler summer, when the tree's growth was not slowed. Another large set of caveats comes from the intricacies of carbon dating. Carbon dating comes from the reality that living things take in carbon 14 from the atmosphere, and then when they die, stop. The atmospheric carbon decays radioactively. However how much C14 is in the atmosphere depends on solar cycles, which means that carbon dating must find measuring rods that show when particular levels of C14 prevailed, and then calibrate off of those. Then there is ordinary measuring problems, contamination, and the fact that trees, even close together, grow at different rates.

One of the sets of tree ring data that I is important here, is the reinterpretation of the Yamal Peninsula data by Biffra, first in 2000, and then updated in 2008. The reason for looking at this data is to attempt to relate the Yamal data to dendrology from Anatolia and other places in the eastern Mediterranean, to see what events are local, and which were global. The Yamal chronology is an important data set, since it offers one of the few checks on Greenland's ice data, which is, essentially, the standard measuring rod for ice cores. This data shows the globalized effect of a sunspot minimum and spike in volcanic activity in the late 18th and early 19th century, and specifically points out the important difference between volcanic activity without a corresponding sunspot minimum (1780's) and with (1810's).

Biffra's data from the Yamal Peninsula was attacked by prominent climate denier Stephen McIntyre, who looked at the data, took trees from a different, but nearby, location, and attacked the interpretation of a particular tree in the data set. He published the results on the web, and Biffra responded. The ravening hoards of climate deniers took this to hurl smears at Biffra, and finally Biffra and a colleague responded in detail here promising a peer reviewed paper to follow. The results of Biffra et. al's review was a small revision in the construction of the data, and points to a different in micro-climate between the sites he used, and the site that McIntyre used. There is only one significant difference at the end of the data, which will be the source of arguments. But it shouldn't be: largely the reinterpretation of the data fits with both Biffra's 2000 and 2008 papers. There's also a kicker.

That kicker is this: the Yamal data clearly shows that the tree rings respond to sunspot minimums with lower growth. The correlation with sunspot measurements matches through out the period of the measurements, up until now. Most particularly in the early 1800's Dalton minimum, and in other more local minimums. The trees of Yamal are important, because they are very responsive to temperature. This means that unlike trees in some other climates, wider rings doesn't imply cooler. The reason this is important for denialism is this: the sun, presently is in a period of accelerated plasma movement on the surface. This means that sunspots form less. Sunspots represent breaks in the surface of the sun, and mean that more radiation escapes from the inside where it takes millions of years to bounce its way outwards. Fusion occurs deep in the sun, and the energy of gravity and the sun's layers contain that energy. Lower sunspots then, means a cooler sun. A cooler sun means a cooler earth than would other wise be the case.

In the early 19th century, there was a cold snap associated with the Dalton Minimum of solar activity. This was compounded between 1810 and 1820 by volcanic events that spewed sulfur into the atmosphere. Sulfur oxides refract and reflect the sun's radiation, and lower solar activity means that they stay aloft longer. The reds of Turner's paintings, the cold of the Santa Claus stories, and the drive for technological progress in the early 19th century are all aspects of how human culture responds to natural changes. This linkage, between sun, temperature, and trees, breaks down in the present. Denialists have seized on the possibilty of a new "Dalton minimum" to say that nothing needs to be done. Instead, the data shows the reverse: even with the present lowered sunspot activity, the earth is almost as warm as it was during the most recent peak of activity. Or, to put it another way, we can't do anything about the sun, and even with the sun cooling the earth, all it is managing to do, is blunt the rise in temperatures.

But this isn't the limit of the short term blunting going on. Consider also the present economic crisis. Humans burn as part of economic activity: for fuel, to clear land for agriculture, and as part of manufacturing. The boom of the last decade was heavily centered in areas that had carbon dense GDP. Or to put it another way, they needed a lot of carbon bang to generate an economic buck. The downturn means that human carbon production has dropped dramatically, thus further slowing, temporarily, global warming. More over, the boom generated a higher concentration of large carbon particular matter, or soot. Soot doesn't stay aloft long, so it does not produce anywhere near as much long term global warming as carbon dioxide, but it produces almost as much while it is up there. More soot meant a spike in temperatures above what Carbon GDP ratios would predict, because the carbon dioxide equivalent of soot is lower than its short term effect.

Lastly, sea levels continue to rise, and ice continues to melt. This means that heat that was otherwise in the air, and thus in air temperatures, is now in the water.

Each of these effects is cumulative, and the result is that were AGW forcing not going on and continuing, we should be having a series of very cool years, as opposed to merely a year which is not the hottest on record. Solar forcing peaked in the early part of the decade.

Scraps of Denial

Credibility, is when someone is believable. Credulability, is when you can believe it if you really want to. Since we are in the middle of an economic downturn, the message that we need to invest in a post-carbon economy is not going to be well received by people who want to consume now. The denialists won't believe, but the reason the public is not as willing to believe is rooted first, in their own circumstances, and second, in what they see around them. Remember, most people don't look at facts, they look at the anecdotes of their own experience, and at other people. They see a committed body of denialism, they hear about "climategate" and see climatologists behaving badly. That for them reads the people.

However the anecdotes are as important. Let me take this graph first:

What this graph shows is the "accumulated cyclone energy" which is a rough way of measuring the strength of hurricanes. ACE represents the sum of the square of the maximum wind speed of a hurricane taken every six hours divided by 10000. So a 100 kph hurricane, adds 1 ACE to the storms, and seasons, total. The graph shows the total ACE in the Atlantic season, and the average per storm. There are a number of interesting things one can draw from this graph, but the point here is that from the mid 1990's to 2005, the Atlantic basin experienced a very active period for tropical cyclones, more so than any period since the 1930's. People believe the anecdotes: they saw storms, this seemed to confirm global warming, they don't see them now, this seems to mean that global warming is passed. In fact, it means nothing of the sort, since the dearth of storms in the last few years if from a warm body of water in the pacific creating upper level winds. Upper level winds shred tropical cyclones, and even if the water is warm, and it was, tropical cyclones don't form.

Let's take an even more blunt anecdote engine, namely where it was in 2009. Not this is from 1970 onward. Where is it? Over the US. Watching this animation drives the point home. The US has had a very large number of colder months over the last 5 years than virtually any other populated land area. To take one example, September 2009 was, globally, the second warmest on record. Now look at the cold patch from this map.

So to look at the numbers: the last few years have not been setting new records every year, the people in the US are seeing cold snaps relative to the last generation of temperatures, and the non-proxy of atlantic hurricanes is missing from the news. America wants to believe that the last decade was simply "the decade from hell" and that it is all over. Natural cycles lead us to think that when a powerful trend peaks and ebbs, it really is over. Global overheating, and an overheating global economy were linked: we sped up a process that is going on. But the last decade was an upward wobble over a long term trend, and the measurements prove it: air and water temperatures continue at high levels, ice continues to melt rapidly even with other forces slowing it down. This is comparable to the early 1990's when volcanic activity and cyclical minimum in temperatures obscured global warming. But we can't count on the sun going into longer term hibernation, and we certainly can't count on volcano gods to bail us out.

So in short, people who don't want to believe, who are standing in the country must alter economic and social arrangements the most, who are seeing an island of chill in an ocean of heat, and who are under economic pressure, are going to be susceptible to propaganda that tells them that they have nothing to worry about. Or at least that they can pass the problem on to others.

Part II tomorrow