Mapping global warming

Prepared and posted by ‘KevinUK’

[Important Update: After coming across this thread entitled ‘Comparing Surface Temperature Records’ on the TreesfortheForest blog and therefore being reminded of the warming/cooling trends in the MGST anomaly chart, I have decided to re-analysis the trends and maps for the time period from 1880 to 1939. It is evident from MGST anomaly chart that 1880 to 1910 was a cooling period followed by a warming period from 1910 to 1939. Consequently I’ve now split the previous analysis for 1880 to 1939 into two distinct time periods i.e from 1880 to 1909 and 1910 to 1939. The results are very interesting so please re-read the whole of this thread]

Recently I’ve been working in collaboration with Verity (vjones) on ‘mapping’ possible global warming/cooling in both the NOAA and GISS GCHN raw and adjusted datasets. This work has resulted from the recent work we’ve been doing on developing a database and user interface to the data (TEKTemp) for storing all the NOAA and GISS raw/adjusted data. TEKTemp is described in more detail in another thread here.

I don’t like seeing raw (or for that matter adjusted data) presented in the form of ‘anomalies’ from a so called ‘reference period’ and so have chosen thus far instead to break with convention and do all my trend analysis of the NOAA/GISS data using actual raw/adjusted temperatures. One of the great advantages of computer programming is that it enables you to repeat repetitive tasks very easily (a DO …. LOOP) and so it’s been possible to create charts that show the raw and adjusted data (and trend lines for each) for the many thousands of stations in the NOAA/GISS datasets.

After performing the trend analysis (linear regression) for each station I then needed a convenient user-friendly way in which to present these seevral thousand charts to anyone who is interested in looking at indiviudal stations and so I came up with the idea of using an interactive map. After a bit of Googling I managed to identify a nice free-to-use Flash map application called ‘DIY Map’ which as you’ll see does ‘just the job’ I need it to do.

The first thing to note is that I’ve analysed the NOAA GHCN and GISS GHCN datasets separately and so have produced completely separate ‘interactive maps’ for each dataset. The NOAA maps are here

NOAA raw/adjusted data interactive maps: http://www.climateapplications.com/MapsNOAA.asp

and the GISS map are here

GISS raw/adjusted data interactive maps: http://www.climateapplications.com/MapsGISS.asp

The map uses an XML file which is loaded into the DIY Map application. The application is written in Flash (Actionscript) and so it can take a while for the map to load all the XML data and display it. As the data is loaded you will most likely see a prompt which says that it is taking sometime for Abobe Flash 10 Player to load the application data. If so then when prompted please click ‘No’ on the prompt that appears and eventually the full colour map be displayed.

The interactive maps (accessible using the links above) allow you to zoom in to a given country just by clicking on a part of that country and you can just as easily zoom out again. Note that there is a colour coded ‘dot’ on the map for each station in the NOAA/GISS dataset. When you hover over a dot it pops up a little ‘summary info’ window which tells you the name of the station, its WMO station code and raw/adjusted trends. If you then click on the dot a new browser window will open showing a chart of the raw/adjusted data for that station. As I get more time I’ll add further info to this station details page.

Each map has a legend which explains the colour coding for the station dots. Most of the maps show colour coded raw/adjusted slopes for the linear trends in the stations raw/adjusted temperature data. Note the units for these slopes are ‘deg.C/century’.

To save some space on this thread and since the legend is the same for all the maps that show raw/adjusted temperature trends here is an image of the slope legend (Figure 1). Note the colours and the corresponding slope ranges when you view the maps that follow on later in this thread.

Figure 1 – Colour coded slope ranges – Map legend

Now let’s make a start by looking at the raw NOAA data as shown in the following JPEG captured image of the NOAA 1880 to 2010 raw data map (Figure 2).

Figure 2 – NOAA 1880 to 2010 raw data slopes (Colour key in Figure 1)

Note that the so-called ‘global warming’ (the slope fitted to all available raw data between 1880 to 2010 for a station) for all stations is certainly not ‘uniform’ throughout the planet. Indeed it indicates that there are certain regions e.g. the US that show warming in certain parts of the country e.g. the North West US compared with cooling in other parts e.g. the South East US. Note these are warming/cooling trends for all available raw data fro the period from 1880 to 2010. Only a few stations are ‘long lived’ i.e have raw data that spans this whole centennial long period. In fact most stations are only ‘short lived’ having raw data that only spans the period from 1950 to 1990. So when you see a ‘dot’ on the following map please bare in mind that the trend for many of the stations may only represent the trend in the raw data from 1950 to 1990 and not the whole 1880 to 2010 period.

Figure 3 – US 1880 to 2010 raw data slopes

Now let’s look at the same NOAA data but this time ‘adjusted’. Note as with th era wdata above that only a few stations are ‘long lived’ i.e have raw data that spans this whole centennial long period. In fact most stations are only ‘short lived’ having raw data that only spans the period from 1950 to 1990. So when you see a ‘dot’ on the following map please bare in mind that the trend for many of the stations may only represent the trend in the raw data from 1950 to 1990 and not the whole 1880 to 2010 period.

Figure 4 – NOAA 1880 to 2010 adjusted data slopes

By comparing Figure 2 (raw slopes) with Figure 4 (adjusted slopes) it is evident that the raw and adjusted slopes, when seen on a global level, aren’t that different. Indeed when viewed on a global level many of the warming/cooling trends seen in the raw data are still evident in the adjusted data i.e. the adjustments do not appear to have that much effect on the ternds seen in the raw data.

This isn’t necessarily the case when it comes to individual stations and indeed as my previous thread on the ‘Physically unjustifiable NOAA GHCN adjustments’ showed, for some individiual stations ‘cooling is turned into warming’ (e.g. Edson) and ‘warming is turned into cooling’ (Mayo). The similarities between Figures 2 and 4 would seem to indicate that the adjustments do not have any significant effect on the general spatial variations in the raw data trends.

Now that is NOAA GHCN version 2 but what about GISS?

Here are the equivalent colour coded raw/adjusted maps for GISS shown in Figures 5 and 6 below.

Figure 5 – GISS 1880 to 2010 raw data slopes

Figure 6 – GISS 1880 to 2010 adjusted data slopes

It’s worth noting that Figure 5 (GISS raw) is not significantly different to Figure 4 (NOAA adjusted). This is not surprising given that GISS takes as its raw input the NOAA GHCN raw data with the US data replaced by USHCNv2 ‘partially adjusted’ data and also adds in raw SCAR data for Antarctica. In effect the GISS raw data for the rest of the world (ROW) is identical to that for NOAA GHCN. Note also by comparing Figure 5 to 6 that the net effect of the GISS adjustments for the US stations is to convert much of the cooling trend for many US stations in the South East of the US to warming stations.

To re-iterate what was satted before, it is important to appreciate that, in all the maps shown so far, the calculated trend slopes have been for all available data between 1880 to 2010. Many of the stations included within the NOAA GHCN (and so therefore also GISS) dataset are not ‘long lived’ i.e. do not have data that spans this complete centennial period. In fact many of the stations only have data from around 1950 through to 1990 i.e. an approximately 40 year period which is known to include a cooling period (approx. 1940 to 1970) followed by a warming period (approx. 1970 onwards). It is generally acknowledged (as evidenced by the MGST anomaly chart seen here) that the period from 1880 to 1910 was a cooling period followed by a warming period from 1910 to 1940, so it would be informative to fit separate slope trends to these 4 distinct warming/cooling time periods i.e. from 1880 to 1909, 1910 to 1939, 1940 to 1969 and 1970 to 2010. Figures 7, 8, 9 and 10 below show the colour coded GISS raw data slope trend maps for each of these periods respectively.

Figure 7 – GISS 1880 to 1909 raw data slopes

Figure 8 – GISS 1910 to 1939 raw data slopes

Figure 9 – GISS 1940 to 1969 raw data slopes

Figure 10 – GISS 1970 to 2010 raw data year mean slopes

Figures 7, 8, 9 and 10 show some very interesting details, so lets start with Figure 7. This shows the slope trends in the GISS raw data for all available data during the period from 1880 to 1909. Note the contrast in warming and cooling in different parts of the globe. Despite warming in the Southern US stations there is a significant warming trend in almost all the Canadian stations along the 49th parallel. There is a cooling trend in the northern Norwegian stations while there is a warning trend in Iceland. There is a signifant cooling trend in most of the Japanese stations as well as in most of the Southern Australian stations. Note the almost complete lack of available data for Africa, Siberia and China and most of South America.

Figure 8 shows the slope trends in the raw GISS data for all available data during the period from 1910 to 1939 and so therefore includes the record warm 1930s as evidenced by the dark red/pink area in the central US. Almost all o fthe US stations are shwoing significant warming trends. Look at the high latitude dark red dots for teh staions in Greenland, Iceland, northern Norway and Russia. Look at the significant cooling trend in most of the Indian and South Eastern Australian stations. It clear that there are substantial differences in the warming/cooling trends between the two global hemispheres. This is demonstrates clear and signifcant natural climatic variability during this time period in different parts of the world.

It is very important to bare in mind the lack of stations in most of the ‘rest of the world’ outside of the US with the exception of Western Europe, Australia and Japan during the period from 1880 to 1939. In particular as can be seen from Figures 7 and 8, there are only a few stations shown in China. Also note that, despite the warming trend in much of the Northern Hemisphere between 1910 to 1939, there is a noticeable cooling trend in most of West and Eastern Australia, India and central Japan during the same time period. What if we had better coverage? IN particular what if we had much better coverage in Siberia and China? If we did then we’d be in a mcuh better positin to compare the warming and cooling periods during thi s1910 to 1939 period with those of the late 20th century.

Figure 9 shows the slope trends in the GISS raw data for all available data during the period from 1940 to 1969. There is a clear cooling trend in almost all of the US, Canada and Western Europe i.e. almost all the Northern Hemisphere with one or two noticeable exceptions, in particular Japan and Eastern Europe in and around the countries bordering the Caspian and Black Seas. The trends for Australia are not significantly diferent to those for the preceding the 1880 to 1939 period.

Figure 10 shows the slope trends in the GISS raw data for all available data during the period from 1970 to 2010. In stark contrast to the preceding 1940 to 1969 period there is a clear significant warming trend in almost all of the US, Canada and Western Europe i.e. almost all the Northern Hemisphere and much of the Southern Hemisphere, also with one or two puzzling noticeable exceptions. For some reason there is a noticeable cooling trend in many of the Eastern Europe stations in and around the countries bordering the Caspian and Black Seas. Again the trends for Australia (and Japan) although generally warming are not that significantly different to those for the preceding 1880 to 1909, 1910 to 1939 and 1940 to 1969 periods. In fact it appears that global warming has never taken place in Western Australia at any time during the 20th Century (8-)).

Its also important to note the very significant warming trend observable in the Canadian stations north of the 49th parallel and in many of the stations in North Eastern China. Why is this? This is certainly worthy of further investigation.

Its also very interesting to compare Figure 8 with Figure 10. Allowing for the lack of coverage from 1910 to 1939 compared to 1970 to 2010, the warming period from 1910 to 1939 is not that dissimilar in extent and magnitude to that from 1970 to 2010. This is a puzzling find as 1910 to 1939 is a period that is generally acknowledged as a period that falls well before the rapid industrial development post the second World War in which the world’s population, largely fuelled by use of fossil fuels expanded enormously thereby leading to significant concerns as to the effect man was subsequenlt having on our planets climate. It woudl seem that base don Figure 8, the 1970 to 2010 warming trend is not ‘unprecedented’ even within th elast century let alone millenium as people like Michael Mann and Phil Jones would have us all believe. Indeed it would appear that the late (i.e 1970 onwards) 20th century warming trend could well be largely due to natural climatic variability just as the 1910 to 1939 warming trend was and not due to largely to man’s emissions of GHGs (i.e. CO2)?

Up until now all the trends presented are year mean temperature trends. Could there be anything to be found if we look at seasonal trends as well as year mean trends? With this in mind, I’ve also produced maps showing seaonal trends (DJF, MAM, JJA and SON) for the 1970 to 2010 period for both the NOAA and GISS datasets. Figures 10 and 11 below show the raw data trend maps for the GISS dataset for DJF and JJA respectively.

Figure 10 – GISS 1970 to 2010 raw data DJF mean slopes

Figure 11 – GISS 1970 to 2010 raw data JJA mean slopes

Now Figure 10 is clearly dramatic! Just look at all those dark red dots (> 5 deg.C/century warming trend) in the Northern US and all of the Canadian stations, and similarly most of the former USSR i.e. Russia, Kazakstan etc, Mongolia and North Eastern China stations! Despite this clearly alarming warming trend, there is at the same same an observed cooling trend in much of central China and, puzzlingly, in much of the Balkans, Greece and Turkey? Looking at the Southern Hemisphere for this DJF seasonal period i.e. summer period in the SH, Western Australia appears to refuse to be warmed!

It is then even more puzzling to contrast Figure 10 with Figure 11 which shows the JJA seasonal period trends. Much of the alarming warming trend evident in the DJF trends for the Northern US and Canadian stations has vanished and in fact has been replaced for some of the Central US stations with a cooling trend. Similarly the many of stations in central China as in Western Australia refuse to show any warming trend! It also looks as though if you want to get a good tan, then ‘the Med’ whether it be the South of France, Italy, Greece or Turkey is a good place to head for and temperatures are clearly rocketing up in the summer. Don’t forget to pack your sun protection cream though!

Seriously though, these seasonal trend maps would appear to indicate that that much of the claimed global warming is hardly global at all. In fact it looks to be more accurately Northern Hemispshere warming, and for that matter primarily Northern Hemispshere WINTER warming! Clearly CO2 is choosey! It’s happy to only take full effect during the winter time in the Northern Hemispshere and even when it does it is also happy at the same time to allow some exceptions. It looks very much like Western Australians need to apply to Kevin Rudd for a carbon tax rebate. Sadly in the UK, out Met Office has fudged the raw data so much that, try as I might, I can’t on the basis of these maps justify a rebate for the UK taxpayer.