34. South Pacific - temperature trends part 2 (east) COOLING

In my previous post I used the temperature data from all the significant temperature records in the region to show that there is no evidence of anthropogenic global warming (AGW) in the western region of the South Pacific. Now I will demonstrate the same for the eastern region.

The eastern region I have defined to be the part of the southern Pacific Ocean between the Pitcairn Islands at a longitude of about 130.1°W and the Pacific coast of South America. This region of the ocean contains far fewer islands than the western portion, and therefore far fewer temperature records. In fact there are only seven station temperature records with more than 480 months of data, of which two are long station records with more than 1200 months. Those latter two are both located on the Chilean islands of Isla Juan Fernandez (Berkeley Earth ID: 11338 and 153937) along with one of the medium records with over 480 months of data (Berkeley Earth ID: 11341). Of the other four medium records, one is from the Pitcairn Islands (Berkeley Earth ID: 155860), one is from San Cristobal in the Galapagos Islands (Berkeley Earth ID: 154642), and two are from the Chilean island of Isla de Pascua, otherwise known as Easter Island (Berkeley Earth ID: 11362 and 153945).

Fig. 34.1: The temperature trend for the eastern South Pacific since 1900. The best fit is applied to the interval 1913-2012 and has a negative gradient of -0.10 ± 0.06 °C per century. The monthly temperature changes are defined relative to the 1951-1970 monthly averages.

The anomalies for each of the seven temperature records used were calculated by subtracting a monthly reference temperature (MRT) from each monthly reading, as described previously. These reference temperatures were calculated by averaging that month's data for the interval 1951-1970. The mean of the seven sets of anomalies is shown above in Fig. 34.1. It can clearly be seen to exhibit a negative temperature trend. In other words, there is no evidence of global warming.

Fig. 34.2: Temperature trends for all long and medium stations in the eastern South Pacific since 1900 derived by aggregating and averaging the Berkeley Earth adjusted data. The best fit linear trend line (in red) is for the period 1913-2012 and has a gradient of +0.71 ± 0.03 °C/century.

Yet the same calculation using Berkeley Earth adjusted data yields a completely different result. The warming since 1900 is now more than 0.8 °C. This is not a consequence of the data, but of the adjustments made to that data. The sum of those adjustments is illustrated below in Fig. 34.3, and indicates that they amount to a correction to the raw data of at least 0.8 °C since 1900, and possibly even more. The data in Fig. 34.3 also indicates that the vast majority of these adjustments are due to the breakpoint adjustment process rather than homogenization.

Fig. 34.3: The contribution of Berkeley Earth (BE) adjustments to the anomaly data after smoothing with a 12-month moving average. The linear best fit to the data is for the period 1913-2012 (red line) and the gradient is +0.81 ± 0.04 °C per century. The orange curve represents the contribution made to the BE adjustment curve by breakpoint adjustments only.

Conclusions

1) The overall temperature trend in the eastern region of the South Pacific over the last 100 years has been negative (see Fig. 34.1). There is no evidence in the raw temperature records of anthropogenic global warming (AGW) in this region.

2) In contrast, the adjusted temperature data constructed by Berkeley Earth exhibits a strong warming trend in its aggregated data of over 0.7 °C per century since 1900 (see Fig. 34.2).

3) The adjustments made to the raw temperature data by Berkeley Earth equate to a change in the overall temperature trend of more than 0.8 °C per century. Almost all of this is the result of adjustments made using the breakpoint adjustment process (see Fig 34.3).

Addendum

The data in Fig. 34.1 above was calculated by averaging the records of the seven stations listed. However, as three of those stations are in close proximity to each other on Isla Juan Fernandez, and another two are likewise in close proximity on Isla de Pascua, it could be argued that relative weightings of 1/3 and 1/2 respectively should be applied to these stations. It so, then the overall temperature trend will change to that shown below in Fig. 34.4. The principal result here is that the new temperature trend with the station weightings is now even more negative: -0.18 ± 0.07 °C per century.

Fig. 34.4: The temperature trend for the eastern South Pacific since 1900. The best fit is applied to the interval 1913-2012 and has a negative gradient of -0.18 ± 0.07 °C per century. The monthly temperature changes are defined relative to the 1951-1970 monthly averages and local weightings are applied to the different temperature anomalies.

33. South Pacific - temperature trends part 1 (west) STABLE

The South Pacific is too large to consider in one discussion, and its weather stations are not evenly distributed. The map below indicates the location of all the long stations (≥ 1200 months of data) and medium stations (480 - 1199 months). It can be seen that the majority of stations are in the western half of the ocean, to the west of the Pitcairn Islands (see the central cross to the right of French Polynesia in Fig. 33.1 below).

 

Fig. 33.1: The locations of all the long and medium stations in the South Pacific by country.

Overall there are only six long stations, four to the west of Pitcairn Island and two on Isla Juan Fernandez off the coast of Chile. In addition, there are 60 medium stations, of which only five are either on, or to the east of, the Pitcairn Islands (longitude 130.1°W). Of these 66 stations, 41 can be classified as having warming trends where the temperature trend is positive and exceeds twice the uncertainty in the trend (see Fig. 33.2 below).

Fig. 33.2: The locations of long stations (large squares) and medium stations (small diamonds) in the South Pacific. Those stations with a high warming trend are marked in red.

In this post I will look at the temperature records in the western half of the South Pacific (west of longitude 132°W). This will also include a couple of stations in Kiribati that are just north of the equator, but will exclude the Pitcairn Islands and the islands off the coast of South America. 

The total number of station temperature records in this region is more than 100, but only 59 have more than 480 months of data, and only four of those are long stations. Averaging the anomalies from these 59 records results in the temperature trend shown below in Fig. 33.3.

 

Fig. 33.3: The temperature trend for the western South Pacific since 1860. The best fit is applied to the interval 1912-1999 and has a gradient of 0.18 ± 0.04 °C per century. The temperature changes are relative to the 1961-1990 average.

The anomaly data in Fig. 33.3 was calculated by finding the monthly reference temperature (MRT) for the period 1961-1990 for each record, and subtracting it from the raw data to determine the temperature anomaly (see Post 4 for details). The anomalies for each month were then averaged.

Only records that had a minimum of 40% of data within this time-frame for any of the twelve months of the year January-December were included in the average for that month. Of the 59 records, one had no qualifying months and two had only nine months out of the possible twelve that satisfied this criterion. Thus one was excluded completely and two were only included for the nine months that their MRTs were valid. The resulting mean temperature trend is illustrated above.

Although the temperature data in Fig. 33.3 has an upward or warming trend from about 1900 onwards, it is very modest (0.18 °C per century for 1912-1999), and it is much less than the fluctuations in the 5-year moving average. The warming is therefore not statistically significant, particularly when compared to the variations in temperature seen before 1895. It should be noted, though, that the data before 1895 is based on only one or two records at most for that time period.

Fig. 33.4: Temperature trends for all long and medium stations in the western South Pacific since 1860 derived by aggregating and averaging the Berkeley Earth adjusted data. The best fit linear trend line (in red) is for the period 1912-1999 and has a gradient of +0.83 ± 0.02 °C/century.

The data in Fig. 33.3 is interesting, but it is meaningless unless we can test it against known control. That control is the equivalent data based on Berkeley Earth adjusted anomalies. This is shown in Fig. 33.4 above. Once again this data exhibits the standard rise in temperature since 1900 of about 1 °C that the IPCC and the climate science community insist we should see. The problem is, that once again, the majority of this warming comes not from the real data, but from the adjustments made to it (see Fig. 33.5 below). As I have noted before, these adjustments are derived from two separate sources: (i) homogenization of the data when constructing the MRTs; (ii) breakpoint adjustments made to different parts of each data set in order to improve the data fitting.

Fig. 33.5: The contribution of Berkeley Earth (BE) adjustments to the anomaly data after smoothing with a 12-month moving average. The linear best fit to the data is for the period 1912-1999 (red line) and the gradient is +0.65 ± 0.03 °C per century. The orange curve represents the contribution made to the BE adjustment curve by breakpoint adjustments only.

Conclusions

1) There is no evidence of a strong warming trend in the aggregated western South Pacific raw temperature anomaly data (see Fig. 33.3).

2) Over 78% of the warming seen in the aggregated Berkeley Earth adjusted data (see Fig. 33.4) is due to adjustments made to the data (see Fig. 33.5), and most of this comes from breakpoint adjustments.

Addendum

The maximum number of temperature records included in the trend in Fig. 33.3 is 57. Between 1900 and 1950 this increases from only 4 to about 24 (see Fig. 33.6 below). The other point to note is that the standard deviation of the temperature fluctuations for most stations in the region is only about 0.5 °C (compared to over 1 °C for most of Australia and New Zealand, for example). This means that the error in the mean temperature trend in Fig. 33.3 is less than 0.08 °C after 1950, but for the period 1900-1950 it varies from approximately 0.25 °C to 0.10 °C. All these uncertainties are, however, much less than the apparent random variations seen in the 5-year moving average for the mean temperature trend. This suggests that the fluctuations seen in the mean temperature trend from 1900-2013 are not the result of a lack of data in the first half of the 20th century or bad data. They are real and indicate the natural behaviour of the temperature record over timescales exceeding 100 years.

Fig. 33.6: The number of sets of station data included each month in the temperature trend for South Pacific (West) shown in Fig. 33.3.

32. Papua New Guinea - temperature trends 0.4°C WARMING (moderate)

I had thought about combining the temperature data for Papua New Guinea (PNG) with that of Indonesia, just as I did with East Timor (Timor Leste) in the previous post. Like East Timor, PNG shares an island (in this case Papua) with Indonesia, so from that point of view it would be logical. However, in the end I decided there was enough data in Indonesia, and extending the analysis to PNG would not only increase the data analysis complexity, but also the geographical area of coverage, and that would be too much. 

Like Indonesia, PNG has only one long station with a temperature record longer than 1200 month (Port Moresby AP - Berkeley Earth ID: 157418). It also has seven medium stations with records of more than 480 months of temperature data, and there are approximately 30 other shorter records that are too small to be useful. One of the medium stations (Port Moresby - Berkeley Earth ID: 19383) is excluded from the following analysis even though it contains data that suggests temperatures in the late 1800s were up to 1.0 °C higher than in the early 20th century. This is because: a) it is close to another long station (Port Moresby AP - Berkeley Earth ID: 157418) which has longer and more complete data in the 20th century; and b) because it has no data after 1941, and so its monthly reference temperatures (MRTs) cannot be calculated for the same time period (1961-1990) as the other stations. For an explanation of MRTs, and how they are used to calculate the monthly temperature anomaly, see Post 4.

Fig. 32.1: Temperature trend for all long and medium stations in Papua New Guineasince 1900 derived using the Berkeley Earth adjusted data. The best fit linear trend line (in red) is for the period 1912-1999 and has a gradient of +0.83 ± 0.03 °C/century.

Averaging the Berkeley Earth adjusted anomaly data from the eight long and medium stations yields the temperature trends shown in Fig. 32.1 above. These are very similar to the versions published by Berkeley Earth and shown below in Fig. 32.2, which suggests that the weightings for each station used by Berkeley Earth in their averaging process were fairly equal.

 

 Fig. 32.2: Temperature trend for Papua New Guinea since 1880 according to Berkeley Earth.

 

The high level of agreement between the data in Fig. 32.1 and Fig. 32.2 allows us to repeat the process for the raw anomaly data without the need for different station weighting coefficients. The result is shown below in Fig. 32.3. 

 

Fig. 32.3: The temperature trend for Papua New Guinea since 1900. The best fit is applied to the interval 1912-1999 and has a gradient of 0.44 ± 0.07 °C per century. The temperature changes are relative to the 1961-1990 average.

It can be seen that once again, the temperature trend derived from the raw anomaly data in Fig. 32.3 is significantly different in its degree of warming compared to that derived using the Berkeley Earth adjusted data in Fig. 32.1 and Fig. 32.2. While there are qualitative similarities (the peaks at 1910 and 2000, and the local minimum around 1965), the overall temperature rise seen in the raw data is much less. At worst, the temperature rise seen in the raw data in Fig. 32.3 is less than 0.4 °C, while the 5-year average in 2010 is barely higher than the peaks in the same curve before 1940.

The 5-year average in 2010 is also only 0.3 °C higher than the 80-year average for 1903-1982. This is hardly conclusive evidence of cataclysmic global warming. In fact the 5-year mean in 2010 is less than two standard deviations above the pre-1982 mean. It is, therefore, within the expected range for natural fluctuations for the given timescale of 110 years.

The data in Fig. 32.3 is also noticeably noisier before 1950 than it is after 1950. This is because there are only two temperature records with data before 1950, and only one of those, Port Moresby AP (Berkeley Earth ID: 157418), is reasonably continuous.

A final point of interest is the qualitative similarity between the data for PNG in Fig. 32.3 above, and that for Queensland shown in Fig. 24.4 previously. The biggest difference appears to be the overall temperature rise which is significantly higher in the case of Queensland (0.74 °C per century compared to 0.44 °C per century for PNG).

Fig. 32.4: The contribution of Berkeley Earth (BE) adjustments to the anomaly data after smoothing with a 12-month moving average. The linear best fit to the data is for the period 1904-2012 (red line) and the gradient is +0.34 ± 0.03 °C per century. The orange curve represents the contribution made to the BE adjustment curve by breakpoint adjustments only.

It is clear that the Berkeley Earth adjusted data for PNG results in almost double the temperature rise since 1900 compared to that found using the raw data. The actual difference is shown in Fig. 32.4 above and amounts to about 0.34 °C per century, most of which is due to breakpoint adjustments.

Conclusions

1) Papua New Guinea has experienced a modest temperature rise since 1960 (perhaps 0.5°C), but overall, temperatures have barely risen by more than 0.3 °C since 1900 (see Fig. 32.3).

2) The temperature trend for Papua New Guinea from 1900 to 2013 is broadly similar to that seen in neighbouring countries and regions (e.g. Indonesia, Australia and New Zealand).

3) The fluctuations in temperature for Papua New Guinea appear broadly consistent with natural variability. The magnitude of these temperature changes clearly challenge the current prevailing paradigm regarding anthropogenic global warming of more than 1.0 °C.

4) The adjustments made to the temperature data by Berkeley Earth have once again had a material and significant impact on the overall temperature trend. It is only with the inclusion of these adjustments that the temperature trend for Papua New Guinea resembles that of the IPCC HadCRUT4 temperature record.

5) The lack of data means that the temperature record of Papua New Guinea before 1950 is extremely uncertain. It can only be speculated upon based on similarities with neighbouring countries.

 

Addendum

The maximum number of temperature records used to derive the mean temperature trend in Fig. 32.3 is seven but before 1940 this reduces to two or less (see Fig. 32.5 below). See here for a complete list of all stations in Papua New Guinea.

 

Fig. 32.5: The number of station records included each month in the mean temperature anomaly (MTA) trend for Papua New Guinea in Fig. 32.3.

 

31. Indonesia - temperature trends STABLE

Indonesia is one of the largest countries in the world and has one of the largest populations at over 267 million. Its archipelago of islands straddles the equator and stretches from a longitude of 95°E to 141°E, a distance of over 5000 km. The country has 53 medium length temperature records with between 480 and 1200 months of data, but only one long station record with more than 1200 months of data (see here). That station is Jakarta Observatorium (Berkeley Earth ID: 155660). It is also the station with the most pronounced warming trend (see Fig. 31.1 below).

Fig. 31.1: The temperature trend for Jakarta Obervatorium since 1866. The best fit is applied to the interval 1866-2013 and has a gradient of 1.82 ± 0.08 °C per century. The temperature changes are relative to the 1961-1990 average.

Overall the temperature rise for Jakarta Obseratorium is nearly 2.7 °C from 1866 to 2013, yet this is not representative of the country as a whole. The medium stations in Indonesia exhibit both warming and stable trends as shown in Fig. 31.2 below. In this case stable trends are defined to be those with a warming that is less than twice the uncertainty. The stations are also fairly evenly dispersed, but are mainly coastal.

Fig. 31.2: The locations of long stations (large squares) and medium stations (small diamonds) in Indonesia. Those stations with a high warming trend are marked in red.

If we average all the records from the long and medium stations we get the overall trend shown in Fig. 31.3 below. Instantly we see a problem. While the overall trend since 1908 appears to be negative (-0.03 ± 0.04 °C per century in fact), there are large discontinuities around 1860, 1902 and 1941.

Fig. 31.3: The temperature trend for Indonesia since 1840. The best fit is applied to the interval 1908-2002 and has a negative gradient of -0.03 ± 0.04 °C per century. The temperature changes are relative to the 1961-1990 average.

 

The reason for this is the low number of station records before 1950, as illustrated in Fig. 31.4 below. For example, between 1866 and 1903 there is only one temperature record available, that of Jakarta Observatorium illustrated in Fig. 31.1 above.

Fig. 31.4: Number of stations per month included in the regional average for the Indonesia temperature anomaly. Only stations with more than 240 months of data in total and sufficient data in the period 1961-1990 are counted.

 

That is not the only problem, though. Low station numbers means that the average can be heavily distorted by one or two rogue datasets, and in this case there are at least three potential candidates in addition to Jakarta Obseratorium in Fig. 31.1. They are shown in the three figures below.

Fig. 31.5: The temperature trend for Christmas Island (Berkeley Earth ID: 154345) since 1900.

Fig. 31.6: The temperature trend for Padang (Berkeley Earth ID: 155706) since 1850.

Fig. 31.7: The temperature trend for Jakarta (Berkeley Earth ID: 15412) since 1866.

The last of these (Fig. 31.7) is another temperature record from Jakarta. Although this has none of the large temperature offsets seen in Fig. 31.5 and Fig. 31.6, it does appear to be as anomalous as the Jakarta Observatorium data in that it is inconsistent with the rest of the data for the country. It is also in close proximity to an existing station (Jakarta Observatorium). So, on the one hand it can corroborate the trend from Jakarta Observatorium, but on the other hand the weightings of both in the overall average trend should be halved.

The remaining question is whether the large temperature falls seen after 1950 in Fig. 31.5 and Fig. 31.6 are real. The suspicion (and it is just a suspicion) is that they are real because similar falls occur in too many other records. For example, they can also be seen in records from Dilli, Bandung and Pontianak. 

 

Fig. 31.8: The temperature trend for Indonesia since 1900 excluding the temperature records from Jakarta. The best fit is applied to the interval 1913-2012 and has a negative gradient of -0.08 ± 0.04 °C per century. The temperature changes are relative to the 1961-1990 average.

So, rather than discarding the data from Christmas Island (Fig. 31.5) and Padang (Fig. 31.6), what happens if we discard both the datasets from Jakarta (Fig. 31.1 and Fig. 31.7) instead? The result is the trend shown in Fig. 31.8 above. This has a negative trend of -0.08 ± 0.04 °C per century, a trend which is also consistent with the data around 1850. The only anomaly is the data from 1903-1913 that is solely from Christmas Island. 

The conclusion from this is that the only part of Indonesia that has exhibited any significant warming since 1850 is the capital and largest city, Jakarta. The rest of the country has seen no temperature rise at all.

Fig. 31.9: Temperature trend for all long and medium stations in Indonesiasince 1850 derived using the Berkeley Earth adjusted data. The best fit linear trend line (in red) is for the period 1871-2010 and has a gradient of +0.94 ± 0.03 °C/century.

What we need to do next is compare the results illustrated above, derived using the anomalies from the raw temperature data, with the equivalent results from Berkeley Earth. Summing and averaging the adjusted anomalies from Berkeley Earth yields the graph in Fig. 31.9 above. These are very similar to the published curves from Berkeley Earth shown in Fig. 31.10 below. Most of the differences are likely due to the inclusion of additional of smaller datasets in the Berkeley Earth plots.

The gradient of the best fit in Fig. 31.9 is +0.94 ± 0.03 °C per century. This is about half that seen in the data for Jakarta Observatorium shown in Fig. 31.1 above, but completely at odds with the data for the rest of the country shown in Fig. 31.8. It suggests that the temperature data from Jakarta has been assigned a greater level of significance (or weighting) and confidence than data from elsewhere in Indonesia. This is perhaps not surprising. The two records from Jakarta are two of the longest and most complete. They also exhibit trends that are both smooth and monotonic. But that does not mean their greater weighting is justified.

Fig. 31.10: Temperature trend for Indonesia since 1840 according to Berkeley Earth.

If we compare the Berkeley Earth adjusted data shown in Fig. 31.9 with the original raw unadjusted anomalies shown in Fig. 31.3, the difference is significant. This difference is shown in Fig. 31.11 below.

Fig. 31.11: The contribution of Berkeley Earth (BE) adjustments to the anomaly data after smoothing with a 12-month moving average. The linear best fit to the data is for the period 1904-2012 (red line) and the gradient is +0.96 ± 0.03 °C per century. The orange curve represents the contribution made to the BE adjustment curve by breakpoint adjustments only.

The data in Fig. 31.11 is shocking. If my analysis is correct, then it suggests that the adjustments made to the data by Berkeley Earth could have added about 0.95 °C to the warming trend since 1904. In other words, virtually all the warming claimed by Berkeley Earth to have occurred in Indonesia since 1904, and depicted in Fig. 31.10, may be the result of their own data adjustments, and not the original data. Moreover, most of this added warming appears to come from breakpoint adjustments.

Conclusions

1) The only warming seen in Indonesia appears to have occurred in Jakarta (see Fig. 31.1). 

2) This warming has been large (about 2.7 °C) and continuous since 1866, which is consistent with its source being population growth linked to increased energy consumption and direct anthropogenic surface heating (DASH), as discussed in Post 14 and Post 29. It may also be a consequence of the urban heat island (UHI) effect.

3) There has been no warming of the overall climate in Indonesia since 1900 (see Fig. 31.8 below).

30. Temperature trends in Antarctica - VARIABLE

If there is one region of the planet that is synonymous with climate change, it is probably Antarctica. Climate change, we are told, is melting the ice cap, the glaciers, the ice shelves and the sea ice. As a result penguins may become extinct in 100 years. Or not, because it turns out there are actually a lot more of them than we thought. So what is really happening in Antarctica?

Well, the honest answer is that we don't really know.  Despite being one of the most studied places on the planet, there is virtually no instrumental temperature data from before 1940. The continent has over 260 instrumental temperature records, but most are less than 40 years in length. In fact only about 56 have more than 240 months of data, of a mere 22 have more than 480 months of data. As the following analysis will show, this is insufficient to draw any accurate or definitive conclusions about the current temperature trends for the continent.

Fig. 30.1: A map of Antarctica showing the locations of all the stations with temperature records containing more than 240 months of data.

Part of the problem with analysing the temperature records of Antarctic is the sheer size of the place. It has almost twice the area of Australia, but the weather stations are not evenly distributed. And given its size, it would be inappropriate to simply aggregate trends from opposite sides of the continent, for the same reasons as for Australia; principally, that they are likely to be totally uncorrelated. When looking at the spatial distribution of stations it becomes clear that most are situated on the coast (see Fig. 30.1 above). Those that are inland are usually at altitude, and as I showed in Post 4, the temperatures in the interior of Antarctica are much lower than elsewhere, and have much higher levels of variability. This implies that they should be analysed and aggregated separately.

In addition, the coastal stations appear to exist in three distinct clusters. The most obvious two are the high densities of stations on the peninsula and around the Ross Sea. In contrast, the stations around the Atlantic coast from longitude 45° W to 90° E are more evenly spread. It therefore seems logical to subdivide the stations into four separate groupings: (i) those found on the Antarctic Peninsula; (ii) the interior stations at altitude; (iii) the stations located along the Pacific coast from the Amundsen Sea in the east, to Queen Mary Land in the west via the Ross Sea; (iv) the stations on the Atlantic Coast from 45° W to 90° E. These four groupings of stations are identified in Fig. 30.1 above. 

 

Fig. 30.2: Number of stations active each month that have more than 240 months of data overall.

 

In Post 4 I looked at the three most significant station records for the interior of Antarctica: Amundsen-Scott Base (Berkeley ID - 166900), Vostok (Berkeley ID - 151513) and Byrd Station (Berkeley ID - 166906). The data for Byrd Station was fragmented, while that for both Amundsen-Scott and Vostok indicated negative temperature trends. No other stations in the interior have more than 240 months of data.

Using 240 months as the cutoff, we find that the number of active stations in the other three regions of Antartica that contain this minimum amount of monthly temperature data never exceeds 20, and in the case of the Atlantic coast, it never exceeds 10 (see Fig. 30.2 above). In addition, most of the data is concentrated from 1980 onwards, and only the Antarctic Peninsula has any data before 1950, but even that is miniscule in terms of its total amount.

Fig. 30.3: The mean temperature for the Pacific coast of Antarctica since 1950. The best fit line is fitted to data from 1973-2010 and has an overall trend of 0.55 ± 0.80 °C per century.

If we calculate the mean temperature trend using the data that is available, the results are not great, at least not if you are a firm believer in climate change. The data for the Pacific coast displays a small amount of warming of 0.55 °C per century since 1973 as shown in Fig. 30.3 above (i.e. 0.21 °C in total). The period 1973-2010 was chosen for the best fit calculation because that time-frame is bounded by two peaks in the 5-year moving average. This means that the peaks do not distort the best fit calculation for reasons that I have outlined in the discussion of Fig. 4.7 in Post 4. 

If the best fit in Fig. 30.3 were to be made to all the data, then best fit trend becomes 1.61 °C per century. The dip around 1960 now pulls down the trend line and increases the warming trend, but is this localized dip in the temperature record permanent or just temporary? The answer is that we don't know because there is insufficient data before 1960 to judge.

 

Fig. 30.4: The mean temperature for the Atlantic coast of Antarctica since 1950. The best fit line is fitted to data from 1973-2010 and has an overall negative trend of -0.21 ± 0.60 °C per century.

If we now turn to the Atlantic coast the pattern is the same. The temperature trend is relatively stable from 1970 to 2010 (see Fig. 30.4). If we measure the trend for 1973-2010 in order to compare directly with that for the Pacific coast, we see that the trend is actually slightly negative and equal to -0.21 ± 0.60 °C per century. But again, extending the fitting to all the data changes the trend to a positive one of gradient +0.49 ± 0.31 °C per century. This is, once again a consequence of a dip in temperatures around 1960. This suggests that the temperature fall is real, and not due to measurement errors, but this dip is large enough to completely change the trend from -0.21 °C per century to +0.49 °C per century.

There is one other similarity with the Pacific coast data: the uncertainties in both trends are very large. This is due to the comparatively short time frame for the available data, which illustrates why long temperature records are so valuable. Even 60 years is not long enough.

Fig. 30.5: The mean temperature for the Antarctic Peninsula since 1940. The best fit line is fitted to data from 1973-2010 and has an overall trend of 2.88 ± 0.77 °C per century.

The notable point about the Antarctic Peninsula is that it is the only region of Antarctica where there is clear evidence of a significant warming trend since 1950. But this is no different from what we have seen in Australia and New Zealand, and in this case there is no data before 1940. That means we cannot say whether this warming is new and permanent, or whether, like Australia and New Zealand, it is just a recovery from a temporary cooling phase. In Australia and New Zealand the temperatures in the latter half of the 19th century were just as high as they are now. In the case of Antarctica we just do not know.

Summary

The analysis above allows us to draw the following conclusions.

1. There has been no warming trend in the interior of Antarctica since 1957 (see Post 4).
   
2. The has been no warming trend on the Atlantic coast since 1950, and probably none of any great consequence on the Pacific coast either (see Fig. 30.4 and Fig. 30.3).
3. The only significant recent warming in Antarctic appears to be around the peninsula (as shown in Fig. 30.5). This warming is, however, no greater than that seen in Australia and New Zealand over the same time period (1950-2010), and that warming was preceded by a cooling of almost equal magnitude (see Post 26 and Post 8).
4. We have no idea what the temperature trend anywhere in Antarctica was before 1940.
   

29. Lateral thought #1 - suburban heating

Question

How much does the average home heat up its environment?

This is really a question that ties in with what I wrote on Post 14. Surface Heating, but I think it illustrates the point at a level that most people can relate to.
 

Answer

Well, we know from Trenberth et al. that the average power of solar radiation incident on the Earth's surface is approximately 161 W/m² (see Fig. 14.1). We also know that this leads to a mean surface temperature for the Earth of about 288 K. We also know from Post 12 (black body radiation and Planck's law) that the emitted surface radiation density scales as T ⁴, where T is the absolute temperature of the surface measured in kelvins, and the emitted radiation must balance the incoming radiation. In other words, both incoming and outgoing surface radiation densities will be proportional to T ⁴. For the outgoing radiation the constant of proportionality will be the Stefan-Boltzmann constant, while for the incoming radiation it will be the Stefan-Boltzmann constant divided by the feedback amplification factor. It therefore follows that if the mean surface temperature were to increase by 1 K to 289 K, then the quantity T ⁴ must increase by 1.40 %. And there are two main ways that this could be achieved. 

The first is to increase the feedback or radiative forcing through an increase in the strength of the Greenhouse Effect. This is what most climate scientists concentrate on, and what they believe is responsible for any temperature changes. But the second possibility is to increase the radiation power absorbed by the surface before the feedback amplification occurs. This could happen if the strength of the Sun's output changes, but more realistically it will happen whenever extra heat is liberated at the surface of the Earth. The amount of heat required to do this will be 1.40 % of 161 W/m², or 2.25 W/m². So an increase of 2.25 W/m² in the incident surface energy density will result in a 1 °C temperature rise (see Post 13 - Case 2).

As I pointed out in Post 14, a major source for such additional heat liberation at the Earth's surface is energy generation and consumption by humans, often for industrial needs. This leads to direct anthropogenic surface heating (DASH) that can raise the temperature of whole countries by as much as 1 °C. But it is not just industry that can significantly heat the local environment.

Consider a typical home. The average household in the UK uses at least 10,000 kWh of energy per year. That equates to an average rate of usage of energy of 1.14 kW throughout the year.

The average land area of homes in the UK is at most 500 m². Most modern housing developments have more than 30 new homes per hectare (see PPG3 guidance paragraphs 57-58); older suburban developments are generally a lot less dense than this; inner city flats and terraced houses are clearly a lot more.

All of this means that the power density for heat escaping from homes will be at least 2.28 W/m² (i.e 1140 ÷ 500). In other words, the energy used by a typical household is more than sufficient to increase the local surface temperature by more than 1 °C. And remember, all this heating has got nothing to do with CO₂ emissions. Nor does this calculation include the energy consumption of commercial buildings, industry or transport.


Conclusion

The energy used by the average household in the UK each day raises the temperature of their local environment by at least 1 °C compared to pre-industrial levels. That will be true irrespective of the source of the energy. Renewables will not help. Nor will cutting your level of CO₂ emissions. This is all down to heat, entropy and thermodynamics.

28. No AGW in Australia? A summary of trends.

 

Fig. 28: 10-year average temperature trends for Australia based on actual raw data (blue curve) and Berkeley Earth adjusted data (orange curve). The gradient of the best fit to the actual raw data (red line) is +0.18 ± 0.02 °C per century. The temperature change is relative to the 1961-1990 average.

 

 

 

My previous ten posts have examined the temperature records of Australia, state by state, and then also examined the combined result. The final results, based on my analytical methods, are summarized as follows.

1) The mean temperatures in Australia since 2000 are at most 0.2 °C higher, and probably less than 0.1 °C higher than those seen in the latter part of the 19th century (see Fig. 26.1).

2) The average temperature in Australia over the course of the entire 20th century was 0.063 °C lower than the equivalent value for the last 50 years of the 19th century.

3) The average temperature in Australia from 1950-1999 was only 0.1 °C higher than the average for the last 50 years of the 19th century.

4) The fluctuations in the temperature of Australia show a scaling behaviour with a fractal dimension of 0.26 (see Fig. 27.2). This suggests that most of the features in the smoothed data, or data averaged over long timescales, are just low frequency noise. Similar effects are seen in the data for most states, and also in the data for New Zealand (see Post 9).

5) The scaling behaviour of the anomalies implies that the 100-year average temperature for Australia would still have fluctuations with a standard deviation of more than 0.10 °C. This is more than the temperature difference observed between the values for the mean temperature of the latter half of the 19th century and that of the latter half of the 20th century. Thus, the temperature rise seen in the latter half of the 20th century is within the range that would be expected based on random chaotic fluctuations.

6) Only Western Australia and Queensland appear to have had noticeably higher temperatures after the year 2000 compared to the late 19th century. This is partly explained by the fact that both states have little or poor data before 1890.

7) The various adjustments made to the individual temperature records by climate groups like Berkeley Earth appear to have had a significant impact on the overall warming trend for Australia when compared with my more simplified (but in my view more justifiable) statistical methodology. This means that the statistical methods used to analyse the data, and their rationale, are of critical importance and need to be thoroughly tested, evaluated, and justified. The first step in doing this should always be to compare the results based on the adjustments with those obtained without the adjustments. That has always been the primary raison d'être of this blog.

8) The overall effect of adjustments made to the individual temperature records of Australia by Berkeley Earth, when compared to my results, has been to partially flatten the curve in Fig. 26.1 before 1900 and to increase the warming trend by up to 0.3 °C after 1900 (see Fig. 26.5). These adjustments are not neutral and completely change the shape of the curve.

9) The overall temperature trend for Australia looks more like a parabola or low frequency oscillation when the raw data is averaged according to my statistical procedure. The effect of the adjustments made to the data by Berkeley Earth is to make the temperature trend look more like a hockey stick (see Fig. 26.4).

Given the shape of the overall instrumental temperature record illustrated in Fig. 26.1, it is difficult to see how this could constitute unambiguous evidence for anthropogenic global warming (AGW). The best (or worst) that can be said about the data is that it is ambiguous. However, it also represents an alternative self-consistent narrative that raises profound questions about the current climate warming zeitgeist.

If my averaging methods for the anomaly data were simplistic to the point of being erroneous, the result would be a mean temperature trend in Fig. 26.1 that was totally uncorrelated with the majority of the individual records from which it was formed. Yet there is no evidence that this is the case. In fact the majority of long temperature records for Australia look very similar to the mean trend shown in Fig. 26.1.

But it is the scaling behaviour that is the killer application. If this phenomenon is real and ubiquitous, then it implies that (almost) everything that is seen in the temperature record is just chaotic noise. The only exception might be the urban heating I described here, and which is clearly important in those parts of the world that have high levels of industry and high population densities. But that is unlikely to be important in most of the Southern Hemisphere.