First let’s establish this as a starting point. When climate science contrarians refer to a “pause” or “hiatus” in global warming, they usually mean that the process of warming of the Earth’s surface caused by the human release of greenhouse gas is not a thing. They are usually implying, or overtly claiming, that the link between CO2 and other greenhouse gas pollutants and surface warming was never there to begin with, and previous warming, warming before “the pause,” was natural variation. Many even go so far as to claim that the Earth’s surface temperature will go down to levels seen decades ago.

“The Pause” is not, in their minds, a slowdown in the rate of warming. It is a disconnect, either there all along or produced somehow recently, between the physics of the greenhouse effect and reality.

Also, the evidence adduced for this “pause” is often bogus. Sometimes badly calibrated satellite data is used to show a flat Earth surface. Er, flat Earth surface temperature. Sometimes a line is drawn from an unusually warm, even under conditions of global warming, El Niño year, to later years, lately excluding record breaking recent warm years, in order to make the line flatter. So, that part of the denier pause is a different kind of lie. See this post and this post for recent research on this issue.

Having said all that, there have been frequent slowdowns and speed-ups in the rate of the planet’s surface warming throughout the entire instrumental record. (Even though the instrumental record begins in 1850 or 1880, depending on which data set you use, greenhouse gas pollution started before that, so some greenhouse warming has been happening all along).

Prior some date, like 1970 perhaps, the up and down variations in surface temperature has been a combination of natural variation and human caused variation, with both being strong factors. The human caused variation includes particulate pollution (from burning coal, mainly) which pushes the temperature down, and greenhouse gas release and its associated effects, which push the temperature up.

For the last third or so of the 20th century, through the present, while both natural and human-caused effects matter, the role of human effects has increased to be the dominant force in the overall trend. The natural variations continue to contribute to the shape of the curve, but this contribution is attenuated by the increased abundance of human generated greenhouse gas.

For the last few years, we have seen several research projects that look at the “pause.” Many of these projects helped to explain the slowdown by showing that it wasn’t really as much of a slowdown as previously thought. For example, some research showed that the surface warming in recent decades has been under-measured because the Arctic (and probably the interior of Africa) were getting warmer faster, compared to other regions, and those areas were under-sampled by the usual data sets. Also, heat has been moving in and out of the ocean all along, and that has had an effect on the surface temperaturews.

But even after accounting for all of these effects, there is still a slowdown.

John C. Fyfe, Gerald A. Meehl, Matthew H. England, Michael E. Mann, Benjamin D. Santer, Gregory M. Flato, Ed Hawkins, Nathan P. Gillett, Shang-Ping Xie, Yu Kosaka and Neil C. Swart have just published a commentary in Nature Climate Change called “Making sense of the early-2000s warming slowdown” that looks at what caused this partial flattening out of the upward trend in global surface temperatures.

Part of this investigation compares the earlier part of the 20th century, when there was a much more significant slowdown in warming, with the more recent slowdown. Fyfe et al note that there are two major contributors to variation in surface temperature aside from greenhouse gases. One is the abundance of aerosols, such as industrial pollution (more of a factor during the earlier hiatus) and the output of volcanoes (such as the 1991 eruption of Mount Pinatubo). The other is multi-decade scale variation in the interaction between the oceans and the atmosphere. The following figure compares the two periods of reduced rate of warming.

As noted in the caption, the two periods are representations of how far off from expected (based on simple greenhouse warming) each period is. It happens that these two periods of slowdown in rate of warming are associated with the negative phase of a major ocean-atmosphere interaction, during which the ocean was eating up some of the extra heat, removing it from the atmosphere. The intervening period of increased rate of warming (from the mid 1970s to about 2000) is associated with a period when this system was in positive phase, putting heat out into the atmosphere. As I’ve noted before, the ocean, which takes up most of the global warming caused heat, is the dog, and the atmosphere is the tail. This is a graph of a dog wagging its tail.

It is not clear when the multi-decade scale ocean-atmosphere interactions will shift to a positive phase. If you look at just the raw numbers, it seems like this may have started a few years ago (around late 2013) but the index for this phenomenon varies enough (goes positive and negative and back over shorter time periods, briefly) that this is not certain. More recently, we have an El Nino causing the belching of heat form the ocean to the air, heating up the surface. This may or may not be related to the multi-decade pattern. Having said all that, we may be concerned that over the next ten years or so, starting about now, we will be in a positive phase during which the rate of warming will be accelerated. This may not be the case. Or it might be the case. No one is actually betting on this yet.

There are two, maybe three, reasons.

First, even though CO2 release from the US may be lower now than it has been in a few years, it is still high (it was high a few years ago, so we’ve reduced to a level that is high!). More importantly, the US has reduced its release of CO2 primarily for incidental economic reasons. With a recession/depression going on, there is less money being spent on things that burn fuel. But, we are also producing more fossil carbon-containing products that we send to other countries, where that fuel is burned, thus releasing the CO2. So, globally, CO2 release is probably as high as it has ever been, more or less.

Second, the greenhouse gasses stay in the atmosphere for a long time. Releasing less does not make what is there go away, really. So if we add less for a couple of years, we still increase the amount.

Third, and less understood, and perhaps not even part of the current calculation of greenhouse gas release, is the extra methane that is being released at large but as yet understudied quantities from drilling operations including those that involve fracking.

So, with those caveats, we have this report from the UN’s World Meteorological Organization:

Greenhouse Gas Concentrations Reach New Record: WMO Bulletin highlights pivotal role of carbon sinks

Geneva, 20 November (WMO) – The amount of greenhouse gases in the atmosphere reached a new record high in 2011, according to the World Meteorological Organization. Between 1990 and 2011 there was a 30% increase in radiative forcing – the warming effect on our climate – because of carbon dioxide (CO2) and other heat-trapping long-lived gases.

At this point I would like to pause and note something important. Here we learn that there has been a 30% increase in warming effects from 1990 onward. This does not mean, however, that Anthropogenic Global Warming (AGW) started in 1990. You will often see Climate Science Denialists refer to events earlier in the last 100 years as evidence that global warming is not real. If global warming supposedly causes large storms, and there was a large storm in the 1930s, or if global warming supposedly causes droughts, and there was the Dust Bowl in the 1930s, then global warming is not real, the story goes. However, global warming is largely the result of the release of Carbon from the burning of coal and petroleum, and that (especially the coal) started way back in the 18th century and really took off in the mid 19th century. Global warming and its effects have certainly been much more significant over the last several decades, but the effects are much older than that. To return to the UN report…

Since the start of the industrial era in 1750, about 375 billion tonnes of carbon have been released into the atmosphere as CO2, primarily from fossil fuel combustion, according to WMO’s 2011 Greenhouse Gas Bulletin, which had a special focus on the carbon cycle. About half of this carbon dioxide remains in the atmosphere, with the rest being absorbed by the oceans and terrestrial biosphere.

“These billions of tonnes of additional carbon dioxide in our atmosphere will remain there for centuries, causing our planet to warm further and impacting on all aspects of life on earth,” said WMO Secretary-General Michel Jarraud. “Future emissions will only compound the situation.”

“Until now, carbon sinks have absorbed nearly half of the carbon dioxide humans emitted in the atmosphere, but this will not necessarily continue in the future. We have already seen that the oceans are becoming more acidic as a result of the carbon dioxide uptake, with potential repercussions for the underwater food chain and coral reefs. There are many additional interactions between greenhouse gases, Earth’s biosphere and oceans, and we need to boost our monitoring capability and scientific knowledge in order to better understand these,” said Mr Jarraud.
“WMO’s Global Atmosphere Watch network, spanning more than 50 countries, provides accurate measurements which form the basis of our understanding of greenhouse gas concentrations, including their many sources, sinks and chemical transformations in the atmosphere,” said Mr Jarraud.

The role of carbon sinks is pivotal in the overall carbon equation. If the extra CO2 emitted is stored in reservoirs such as the deep oceans, it could be trapped for hundreds or even thousands of years. By contrast, new forests retain carbon for a much shorter time span.
The Greenhouse Gas Bulletin reports on atmospheric concentrations – and not emissions – of greenhouse gases. Emissions represent what goes into the atmosphere. Concentrations represent what remains in the atmosphere after the complex system of interactions between the atmosphere, biosphere and the oceans.

CO2 is the most important of the long-lived greenhouse gases – so named because they trap radiation within the Earth’s atmosphere causing it to warm. Human activities, such as fossil fuel burning and land use change (for instance, tropical deforestation), are the main sources of the anthropogenic carbon dioxide in the atmosphere. The other main long-lived greenhouse gases are methane and nitrous oxide. Increasing concentrations of the greenhouse gases in the atmosphere are drivers of climate change.

The National Oceanic and Atmospheric Administration’s Annual Greenhouse Gas Index, quoted in the bulletin, shows that from 1990 to 2011, radiative forcing by long-lived greenhouse gases increased by 30%, with CO2 accounting for about 80% of this increase. Total radiative forcing of all long-lived greenhouse gases was the CO2 equivalent of 473 parts per million in 2011.

The report goes on to state that CO2 is the single most important human generated greenhouse gas, but also discusses methane, which I mentioned above, and discusses Nitrous oxide as well.

(Thanks to Brad Johnson for the info on hydrocarbon exports.)

So, one could say that the last 20 years have largely been wasted when it comes to reforming how we do thing on this planet in a way that would reduce the release of fossil carbon into the atmosphere. One could say that whatever ill effects our planet suffers over coming decades that occur because of this delay is the responsibility … the fault … of those who were pushing these lies over recent decades. And, just to be clear, the comparison I just made, between 1990 and now, is the short version; We understood what was happening well before 1990. And the lies and deceit and bought and paid for denialism has been going on for much longer.

And now we have 2011. This year, we have experience the most expensive year of weather disasters in our history. The total cost of disasters this year, and we are still only in July, is in the tens of billions of dollars, perhaps 32 billion. A typical year in recent times has been about 6 billion. The cost in human lives has also been high, with over 600 people killed from flooding, tornado outbreaks, and other storms.* It is hard to attribute specific damage or death to global warming, but guess what: It is also hard to attribute specific deaths to influenza during the influenza season, but we manage to count the effects of flu anyway. For the latter, certain categories of morbidity or mortality which are known to be linked to influenza are monitored all year, and we see an increase during flu season while at the same time a smaller sample of people are showing up with influenza demonstrated through blood tests. Similarly, with global warming effects, we can see a broad association between heat and storms, and we know where that heat is coming from. We know that because the science on this is pretty good.

2011 will almost certainly turn out to be the hottest year on record. 2010 and 2005 were previously tied for the hottest. June 2011 was the 315th consecutive month above the 20th century average. The last time we experience a month with global temperatures lower than the 20th century average was February. February 1985.* Five years before I wrote that article I mentioned.

The arctic sea is no longer covered with ice as it used to be. Now, the ice cycles are fundamentally different. The change that is happening there is difficult to track and a few more years needs to pass before we’ll fully understand it. But ice that has not melted in many many years has melted, and ice that normally forms no longer does.

When I wrote a few weeks back that global warming denialists were responsible for making the world our grandchildren would grow up in a more dangerous place, I received death threats from those denialists. One gentleman invited me to his ranch in Texas so he could shoot me to death. Others were less direct in their threats¹. Still more did not make threats but certainly did write me obnoxious emails. Several demanded that I open my blog up to be their public forum, where they could spread their lies. The reason I mention this is just so you know … this is not a rational debate, and has not been for some time. Many of the people who used to debate these issues with me, here and elsewhere, and who were, of course, wrong about climate change but who were otherwise reasonable people, have shifted strategy: They no longer discuss this issue at all. Clearly they have changed their minds, or at least, learned that what might have been thought of as a fools errand is now merely an error of fools. And they’ve learned to shut up. The only ones left denying the science are crazy people. Truly.

This Sunday, Mike Haubrich and I will be joined on Atheist Talk Radio AM 950 by two scientists deeply involved with research related to global climate change, Kevin Zelnio and John Abraham.

Kevin Zelnio is a science journalist and blogger at Scientific American Blogs and at Deep Sea News. He has written on the effects of the change in climate on the ocean (and our fisheries), and blogs about invertebrates that live in the sea and other topics.

John Abraham is a Professor of Mechanical Engineering (Heat Transfer and Fluid Mechanics) at St. Thomas University in St. Paul. Aside from his extensive work in the science, he is also well known for a response he crafted to a presentation made by climate change denialist Chrisopher Monckton at Bethel University. Here is John’s presentation.

Details of the radio show are here.

I’m assuming this will be the last time we’ll be discussion global climate change with any reference to denialism. We need to get on with the work of addressing this crisis.

¹That was Bob Clark of the Circle KB Ranch, 26309 Old Owen Road, Monroe, WA 98272-9071 (Land Line: 360 794 7387; Bob’s Cell: 206 459 5802; Kay’s Cell: 206 459 5865; Truck’s Sky Phone: 425 330 9377) who claims to be retired with an honors degree in Physical Chemistry. I assume that’s an associates degree.