September 9, 2008

Another Message from Kyoto

Do a web search for “Kyoto and Global Warming” and you will be pointed to a stunning 4.5 million sites. For many people in the world today, Kyoto could never be located on a map, few would know that it was once the imperial capital of Japan, and for that matter, few would even know that Kyoto is in Japan. It really wouldn’t matter, for most importantly, almost everyone knows Kyoto has something to do with global warming, “Kyoto” is something President Bust did or didn’t do, and it led to more global warming, right?

A meeting in Kyoto, Japan resulted in an agreement by the United Nations aimed at slowing down the buildup of greenhouse gases. The resulting “Kyoto Protocol” was part of the International Framework Convention on Climate Change; the Protocol was adopted on December 11, 1997 by the Third Conference of the Parties which was meeting in Kyoto (all of this can be traced back to the famous 1992 Earth Summit in Rio de Janeiro). If you had been on the “Conference of the Parties” circuit ever since, you would have enjoyed wonderful visits to Berlin, Geneva, Kyoto, Buenos Aires (twice), Bonn (twice), The Hague, Marrakech, New Delhi, Milan, Montreal, Nairobi, and Bali! Nothing says “fight global warming” any more than a never-ending world tour!

As you might have heard, 182 parties have ratified the Kyoto Protocol, but the United States has not ratified the treaty, much to the chagrin of many world leaders and every environmentalist on the planet No matter what the weather calamity anywhere in the world, someone is quick to point out that global warming is the cause and the mess could have been avoided had President Bush et al. ratified the Kyoto Protocol!

With interest in Kyoto and Japan, we found information in a recent article in Weather more than interesting; the article was written by Professor Takehiko Mikami of the Department of Geography at Tokyo Metropolitan University. Mikami begins the piece noting that in Japan, there are “several kinds of documentary sources for reconstructing climatic variations in historical times: 1) Cherry-tree-flowering date records since the eleventh century; 2) Lake-freezing date records since the sixteenth century; and 3) Weather diary records since the eighteenth century.” We at World Climate Report love real-world data, and we couldn’t wait to learn about the climate history of places like Kyoto.

Figure 1 shows the flowering dates of cherry blossoms, and the dates come from information in old diaries and chronicles regarding cherry blossom festivals held in Kyoto. The dates are then converted into March temperatures using statistical methods, and the temperatures appear in the figure as well. As case can certainly be made warming over the past 200 years, and global warming advocates might be thrilled to see warming since the beginning of the Industrial Revolution. However, Mikami states “The results indicate warmer periods during the eleventh to thirteenth centuries (in the Medieval Warm Period) and relatively colder periods during the sixteenth to eighteenth centuries (the ‘Little Ice Age’) with large year-to-year variability”. When viewed over the past 1,000 years, there is certainly (a) little unusual about the recent warming, (b) no apparent correlation between atmospheric carbon dioxide levels and temperature variations in Kyoto, and (c) a possibility that the recent warming was induced by the urban heat island of the growing city.

Figure 1. (a) Year-to-year variations in full flowering dates of mountain cherry trees in Kyoto since AD 1001, and (b) variations in March mean temperatures since 1001 estimated from full flowering dates of cherry trees in Kyoto city (from Mikami, 2008).

Next up is the information from lake-freezing dates from Lake Suwa located in central Japan. For a variety of reasons, local villagers have recorded the lake-freezing dates since AD 1444. During a cold winter, the lake would be frozen by mid-December while during warm winters, the freeze would be delayed until the end of February (some warm winters produced no freezing of the lake). A relatively simple statistical procedure was used to link freeze dates to winter temperatures using the period 1945 to 1990, and the transfer equation could then convert freeze dates into temperatures. In discussing Figure 2 (below), Mikami states “Although the lake-freezing records are not continuous from the late seventeenth century to the nineteenth century, a clear warming trend stands out during the final stage of the Little Ice Age from the 1750s to the 1850s. On the other hand, the coldest period since the fifteenth century was the early 1600s, when reconstructed mean winter temperatures were about 1 to 1.5 deg C lower than at present (1961–1990).” A case can be made for warming, but it all occurred at the end of the “Little Ice Age”.

Figure 2. Year-to-year variations in December/January temperatures at Lake Suwa during the period 1444–1870 (reconstructed) and 1891–1995 (observed)(from Mikami, 2008).

Next we learn that “In Japan, a large number of weather diaries from most parts of the country are preserved in local libraries and museums.” One diary from Tokyo was used to reconstruct summer temperatures from 1721 to near present. Again using statistical procedures, the author produced the reconstruction of summer temperatures shown in Figure 3. Mikami notes “From 1721 to 1790, temperatures are estimated to have been around 1 to 1.5 deg C lower than at present. During this period, July temperatures show large year-to-year variability with the lower values below 22 °C in 1728, 1736, 1738, 1755, 1758, 1783, 1784 and 1786. It should be noted that the temperatures in the 1780s were often extremely low with large inter-annual variations. In the summer of 1783, they experienced an extremely poor rice harvest under the influence of exceedingly cool and wet climate conditions, and this unusual weather brought a historic severe famine in Japan”. Cold sucks!

Mikami then states “On the other hand, it was rather warm in the nineteenth century, especially in the 1810s and the early 1850s with the higher values above 26 °C in 1811, 1817, 1821, 1851, 1852 and 1853. Among these warmer periods, the 1830s, late 1860s and late 1890s were relatively cool decades, and great famines occurred recurrently in the 1830s as appeared in the 1780s. July temperatures reached their lowest level around 1900, when 11-year mean temperatures were the same as those around 1740.” Mikami warns “it should be remembered that Tokyo has one of the strongest urban heat-islands in the world and this is likely to have influenced such temperature trends.”

Figure 3. Combined time series of reconstructed (broken line) and observed (solid line) July temperatures
in Tokyo for 1721–1995 (11-year running means)(from Mikami, 2008).

With Kyoto and Japan being almost synonymous with global warming policy, it is more than interesting to note how little “global warming” appears in any of the long-term climate records extracted from historical documents from that area.


Mikami, T. 2008. Climatic variations in Japan reconstructed from historical documents. Weather, 63, 190-193.

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