Tag Archives: climate change graphics

The Global Warming Hiatus, 2013, And Some Data (#FauxPause)

First, there is no hiatus. Climate science skeptics claim that warming stopped in 1998. It didn’t. Stefan Rahmstorf has a nice post placing 2013 in context with the most recent data, HERE. Just click the “translate” button to read it in your favorite language.

UPDATE: Stefan’s post is now HERE on Real Climate, in English.

Stefan has a bunch of great graphics that you will enjoy. Following his lead I’ve decided to make a graphic or two myself.

First, the data. NASA has this data to which people often refer when discussing global warming. I took that database and fixed it up a bit. I deleted the first year because there’s some missing data and who cares about only one year anyway. Then, I converted all the values to degrees C rather than hundreds of degrees off a baseline. I also calculated a rank for each year in reference to the entire database. You can download the data as a comma delimited file here. Let me know if that link doesn’t work for you, I’ll be happy to send you the file. Please cite the original (linked to above) if you use this.

Using these data I made this handy graphic showing “surface temperatures” (air and sea surface) over time from 1881 to the present.

When people talk about the hiatus in climate change, or the pause in climate change, what this means is that the slope of the temperature curve for a particular period of time is at or near zero, or negative. What actually happens is that the slope of the curve for a given interval, say 10 years, goes up and down over time. If the temperature was varying around a mean, and not going up over time, the sum of those slopes would be zero, but if there is an average increase in temperature the sum of all the different slopes (of a given interval) one can calculate will be positive.

This is actually a slightly strange way of looking at the data, but I think it is constructive, especially given that the so-called-pause is a dead horse and we are hear to beat it. Look at the chart above. Imagine taking any given ten year period and calculating a slope for that period. Then another and another and another, until you’ve measured out a slope for every ten year period … not just every ten years, but every possible interval of ten consecutive years. This would be a “moving slope” and a graph of it would look like this:


What this shows is that for the vast majority of ten year intervals since 1889 (so the first interval is 1880-1889) the slope of the temperature curve is positive, going up, increasing. It also shows what looks like a remarkably periodic increase and decrease in this slope, with only a few dips below zero. That’s presumably due to oscillations such as ENSO or other factors. Also, most of those dips are from fairly far back in time, and this happens rarely in recent years. We are currently in a period of positive change (upward temperature swings) but currently reduced. But if you look at this graph you can see that there are OFTEN periods of time when the upward slope is very high and other periods when it is very low but still above zero almost always. I hope this helps put the “hiatus” into perspective.

I also made this graph of each year’s rank for the entire period represented by the data set.

Screen Shot 2014-01-26 at 7.03.12 PM

Again, this is a slightly unusual way of depicting the data, but it may be helpful. All of the highest ranked years … top ten or so … are from very recent time. The graph has grid lines at every 10 ranks. This lets you quickly identify the period of time over which the top 10, or 20, or 30, or whatever, warmest year according to this data set occurred. There are no top ten years prior to about 1998. All of the top 30 warmest years post date the early 1970s. And so on.

OK, so let’s look at the hiatus again. The hiatus is supposed to be a period of no global warming since 1998. Here’s a closeup of the original chart (above) for that period of time:


What we see here, with the trend line included to make it easier to read, is an increase in global temperature, on average, during this so called hiatus period. But, by picking 1998 as a starting point, climate science denialists have managed to flatten the curve out quite a bit. That’s called cherry picking.

Now let’s arbitrarily double the period of interest, to include the entire so-called hiatus and the same amount of time back before the so-called hiatus. What does the graph look like then? Here, I’ve tried to keep all the scales the same so you can see the shorter “hiatus” period as part of this larger graph. You can also see that 1998 was an exceptionally warm year, which is why you’d want to pick it as the beginning of your fake hiatus period if you were a damn liar. Have a look.


Let’s look at those so called hiatus years in yet another way. Here, we have the graph of the temperature by years (with the upward sloping trend line indicating continued warming even though it is supposed to be a “pause”) and at each node I’ve written in the rank order of the year for the instrumental record. Note that tied years share a number. Basically, this period of “hiatus” is a very very warm period indeed, with temperatures trending upward during the entire period, looking only at the earth’s surface. (Elsewhere we’ve discussed how there is also heat going into the oceans. See links below.)


Since the climate science denialists have chosen a period of time of 16 years to describe a so-called “hiatus” which is not really a hiatus, I thought it would be fun to chunk out the data for the entire time period into 16 year intervals, starting with the most recent and going back to 1886. When viewed using these time intervals, we see overall warming with the most recent years seeing accelerated warming. Have a look:

Screen Shot 2014-01-26 at 7.07.36 PM

These are all first drafts and if I get reasonable suggestions I may make new versions with corrections, additions, etc.

Global warming. It’s for real.

Other posts related to the #fauxpause:

The Truth About Global Warming’s Famous Slowdown

Why you sound so stupid when you say “global warming has stopped”

About That Global Warming Hiatus… #Fauxpause

Arctic Sea Ice: A System In Collapse

For the last 25 years or so there has been a decrease in the amount of ice that remains on the surface of the Arctic Ocean every summer. This is a trend that can be attributed to global warming, which in turn, can be attributed to the steady release of previously fossilized Carbon to the atmosphere by the burning of coal, oil, and natural gas. But over the last few years, this decrease in ice has been much more dramatic. The trend has steepened. The formation and melting of ice has to do with air and water temperatures. This in turn can be affected by how much ice there is, because ice reflects energy from the sun, while open water absorbs it. There are other factors as well having to do with the distribution of air masses. It is all very complicated, but the bottom line is that reduction in ice can lead to further reduction in ice. It is quite possible that the recent very steep declines in Arctic sea ice represents not just a trend that happens to be, for random reasons, a bit steeper than usual for a while, or that it is even a long term change in the rate of inter-annual loss. Rather, it could be that the phenomenon of summer sea ice in the Arctic is simply something that is no longer sustainable because of new conditions caused by climate change, and that the sea ice we see now is mainly the remnant of a previously existing, no longer operational, system. Time will tell. Probably not much time, in fact. If the recent dramatic reduction in summer ice is a random blip, then the amount of summer sea ice over the next five years or so may go up rather than down. If the recent reduction is a result of a different relationship between sun’s energy, water temperature, air temperature, and ice formation, then over the next five years or so the trend of declining ice should continue and at some point settle on a new equilibrium with variation around a new mean.

There is probably a rule of thumb that could be applied here. One of the most important Quasi-cyclic climate variations, the El Niño–Southern Oscillation (ENSO), has an average period of about 5 years. Let’s assume that a full cycle is a strong El Niño followed by opposite conditions for the same period of time. Conservatively, we might want to let a climate change in some part of the Earth’s system to run for 10 years without changing direction before we can be pretty sure that it isn’t just a perturbation that will later readjust. Consider a ten-year rule of thumb in relation to the following graphic showing Arctic sea ice from 1979-2012:

That’s a nice graph, produced by Andy Lee Robinson. Robinson created this very nice looking animation from data he had earlier depicted in a simpler two dimensional form, which actually is in some ways more dramatic (It’s a moving GIF, click to watch it move, then come back!):


The story behind these graphs, including data sources, is summarized in this post by Peter Sinclair.

In these graphics, the last seven years show sea ice surface area occurring several years in a row at a much lower average than previously, and with a steady decline continuing. But there is a strong declining trend that actually starts earlier, closer to 2002. It is a little hard to put an exact year on this. If there is a new equilibrium being reached, when we look back on these data in a decade or so, where would we start the trend? Late 1990s? 2000? 2002? 2007? Hard to say.

But there is a problem with this view of the Arctic: The sea ice that rebuilds every winter starts with a core of “old ice” which during cold trends is added to every year. This is thick ice. A huge amount of the volume of sea ice in a give year, say back in the 1970s, is actually stacked up vertically. This ice has been melting as well, and climate scientists who study the arctic regard the decline of this old ice as more important than the simple reduction in surface area. In other words, the important area here might be volume rather than surface area. Volume is harder to measure over the long period because the instrumentation needed to make good volume estimates is has not been applied to the Arctic for very long, but we do have an idea of what has happened.

Have a look at this demonstration of the importance of volume:

The following graphic and the video I just showed you are both from Andy Lee Robinson:

If we look at volume rather than surface area over time, in a graph from here, we get something like this:

Each of the colored ringoids on this graph is a decadal average of ice volume around the seasonal cycle. The drop in volume each year is a function of both decreased ice formation in the summer and decrease in volume, but the latter, volume, is driving the change you see here. Noticed that each decade has less ice volume than the previous decade. Also noice that the 2000-2009 decade is dramatically smaller in volume than the previous decades, and the last few years have at least the same amount of decrease. This shows that the dramatic drop in Arctic sea ice may be a thing that has been happening both very recently and for enough years that the 10-year rule of thumb may already apply. We’ll see what happens over the next few years.

Extreme Weather in the US Northeast and Climate Change

This graph shows the extremes in one-day precipitation in a given month relative to the amount of precip in that month for the Northeastern US. So, if the green bar is at 30%, that means that that 30% of month’s precip fell in one event. The way this is computed is a little complicated because it is hard to define an “event” in time and space in relation to the time and space coordinates (as it were) we normally use. Check the source of the graph for a more detailed explanation. The point of this graph is that the opposite is true from what many expect: It isn’t the case that the snow was deeper back when you were a kid. It’s deeper now! (Check out this blog post for an explanation for why you may have misremembered your childhood.) There are a number of contributing factors to a pattern like this, with increasing extreme events, but the best way to think of this may be as an increase in the bimodality of the water cycle. Dry events are dryer (you may have noticed widespread drought) and wet events are wetter (as shown in this graph).

Northeastern US extreme precip events; more extreme rain and snow storms in more recent times.
From NOAA National Climatic Data Center.

“Belief” in Climate Change, The Weather, and Political Party

It seems that people “believe” in climate change (really, global warming in particular) when it it hot out more than at other times. And by “people” I mean the population in general. It turns out that Democrats don’t change their position on climate change as the temperature outside changes (they already know it is real) and Republicans do a little (because it is true and a small number of them will put reality before politics). Meanwhile, those darn Independent voters who have somehow taken over our democracy for some very poor reasons (IMHO) wildly change their beliefs literally on the basis of the ambient temperature. Talk about sticking your finger in the air and seeing which way the wind blows before making an important decision!

Here’s a graph showing this relationship (HT Peter Gleick):

Independents and climate change belief
Belief in Climate Change, Political Party, and Temperature.

This is based on research done at the University of New Hampshire, summarized in this press report:

Climate Change Beliefs of Independent Voters Shift with the Weather, UNH Study Finds

DURHAM, N.H. – There’s a well-known saying in New England that if you don’t like the weather here, wait a minute. When it comes to independent voters, those weather changes can just as quickly shift beliefs about climate change.

New research from the University of New Hampshire finds that the climate change beliefs of independent voters are dramatically swayed by short-term weather conditions. The research was conducted by Lawrence Hamilton, professor of sociology and senior fellow at the Carsey Institute, and Mary Stampone, assistant professor of geography and the New Hampshire state climatologist. The research is presented in the article “Blowin’ in the Wind: Short-Term Weather and Belief in Anthropogenic Climate Change” in the American Meteorological Society journal Weather, Climate, and Society.

“We find that over 10 surveys, Republicans and Democrats remain far apart and firm in their beliefs about climate change. Independents fall in between these extremes, but their beliefs appear weakly held — literally blowing in the wind. Interviewed on unseasonably warm days, independents tend to agree with the scientific consensus on human-caused climate change. On unseasonably cool days, they tend not to,” Hamilton and Stampone say.

Hamilton and Stampone used statewide data from about 5,000 random-sample telephone interviews conducted on 99 days over two and a half years (2010 to 2012) by the Granite State Poll. They combined the survey data with temperature and precipitation indicators derived from New Hampshire’s U.S. Historical Climatology Network (USHCN) station records. Survey respondents were asked whether they thought climate change is happening now, caused mainly by human activities. Alternatively, respondents could state that climate change is not happening, or that it is happening but mainly for natural reasons.

Unseasonably warm or cool temperatures on the interview day and previous day seemed to shift the odds of respondents believing that humans are changing the climate. However, when researchers broke these responses down by political affiliation (Democrat, Republican or independent), they found that temperature had a substantial effect on climate change views mainly among independent voters.

“Independent voters were less likely to believe that climate change was caused by humans on unseasonably cool days and more likely to believe that climate change was caused by humans on unseasonably warm days. The shift was dramatic. On the coolest days, belief in human-caused climate change dropped below 40 percent among independents. On the hottest days, it increased above 70 percent,” Hamilton says.

New Hampshire’s self-identified independents generally resemble their counterparts on a nationwide survey that asked the same questions, according to the researchers. Independents comprise 18 percent of the New Hampshire estimation sample, compared with 17 percent nationally. They are similar with respect to education, but slightly older, and more balanced with respect to gender.

In conducting their analysis, the researchers took into account other factors such as education, age, and sex. They also made adjustments for the seasons, and for random variation between surveys that might be caused by nontemperature events.

Credit for graphic: Lawrence Hamilton and Mary Stampone/UNH

Annual Amount of Carbon Released Into Atmosphere

Here are two graphs that show the amount of carbon released into the atmosphere, mainly as CO2 and mainly form the burning of fossil fuels, per year, from various sources for a long span of time. Both graphs are based on the same data set. the first graph was created by the Carbon Dioxide Information Analysis Center and shows the breakdown between different sources of carbon. The second graph, which I made, simply shows the total, and over a shorter time span to make it easier to use for other purposes.



Arctic Sea Ice Extent (reduction of): Graphic

Here’s a graph showing the extent of arctic sea ice as measured directly and indirectly for the last several hundred years:

Arctic Sea Ice Melting
Solid red line is the reconstructed 40 year smoothed, late-summer Arctic sea ice extent from Kinnard et al. (2011). Shaded area shows 95% confidence interval. Blue dashed line shows modern observations.

This graphic is from Skeptical Science, where you can also download a higher res version and learn more about the background for these data. Also, on that page is a link to a large number of useful graphics related to climate change.

How can anyone think that global warming isn’t real? Here’s how:

Skeptical Science is a great source for information about climate change. One of the coolest things they’ve got over there is a moving GIF demonstrating how the folks in the climate science denialism industry try to convince people that global warming isn’t real. This involves cherry picking data to show small segments of time with either flat lines (no warming) or decreasing lines (cooling), and ignoring that the longer term pattern is one of a distinct increase.

Here’s the graphic:

global warming hoax vs.  real.
How to make it look like global warming is a hoax!

For more information about this graphic, and other great stuff, check out the Skeptical Science web page.

Global Temperatures since 1850

Anthropogenic global warming is a long term phenomenon that is caused by the release of Carbon, in the form of Carbon Dioxide, from fossil deposits, though burning of fuels such as oil, natural gas, and coal. There are other human causes as well, but some of those relate to the use of fossil fuels (such as the leakage of methane gas from oil extraction operations, or from delivery pipelines).

The evidence for warming comes from a variety of sources, but mainly from land based thermometer stations from about the mid 19th century and later, higher tech measurements such as satellites.

The following graph is provided by the National Climatic Data Center and comes with its own caption attached, providing the original source:

increase in global temperatures global warming
Change in global temperatures since 1850