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Old masters, new climate lessons?

Paintings of striking sunsets show the effects of huge volcanic eruptions on climate. Now, David Adam reports, scientists are analysing artists’ works to see if they can help improve computer models used to simulate global warming.
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The Fighting Téméraire tugged to her last Berth to be broken up by JMW Turner, 1838

The English landscape painter JMW Turner said his work was not to be understood but “to show what such a scene was like”. Now global-warming experts are taking advantage of his prosaic nature to improve their predictions of the consequences of climate change.

The scientists are analysing the striking sunsets painted by Turner and dozens of other artists to work out the cooling effects of huge volcanic eruptions. By working out how the climate varied naturally in the past, they hope to improve the computer models used to simulate global warming.

The team, at the National Observatory of Athens, is using the works of old masters to work out the amount of natural pollution spewed into the skies by eruptions such as on Indonesia’s Krakatoa in 1883. Reports from the time describe stunning sunsets for several years afterwards, as the retreating light was scattered by reflective particles thrown high into the atmosphere. By studying the colour of sunsets painted before and after such eruptions, the researchers say they can calculate the amount of material in the sky at the time.

Christos Zerefos, the research leader, said: “We’re taking advantage of the attitudes of famous painters to portray real scenes they were looking at. This is the first attempt to analyse this old art in a scientific way, and tells the story of how our climate has varied naturally in the past.”

The results will feed into the scientific study of a phenomenon called global dimming, which is caused by air pollution blocking sunlight. Some experts believe this has acted as a brake on global warming, and that climate change could accelerate as air pollution from industry is reduced.

Zerefos and his team looked at natural global dimming caused by volcanoes, the results of which can be severe. The eruption of Mount Tambora in Indonesia in 1815 threw out so much material that it triggered the notorious “year without a summer”, which caused widespread failure of harvests across Europe, resulting in famine and economic collapse.

The team found 181 artists who had painted sunsets between 1500 and 1900. The 554 pictures included works by Rubens, Rembrandt, Gainsborough and Hogarth. They used a computer to work out the relative amounts of red and green in each picture, along the horizon. Sunlight scattered by airborne particles appears more red than green, so the reddest sunsets indicate the dirtiest skies. The researchers found most pictures with the highest red/green ratios were painted in the three years following a documented eruption. There were 54 of these “volcanic sunset” pictures.

Zerefos said five artists had lived at the right time to paint sunsets before, during and after eruptions. Turner witnessed the effects of three: at Tambora in 1815; Babuyan, Philippines in 1831, and Cosiguina, Nicaragua, in 1835. In each case, the scientists found a sharp change in the red/green ratio of the sunsets Turner painted up to three years afterwards.

Writing in the journal Atmospheric Chemistry and Physics (ACP), the scientists say the redder sunsets seen in paintings “can be tentatively attributed to the volcanic events, and not to abnormalities in the colour degradation due to age, or other random factors affecting each painter’s colour perception”.

The scientists used the red/green ratios to estimate the amount of airborne dust produced by each volcano. The results, they say, are remarkably similar to estimates prepared from historical observations, early measurements and material found in ice cores.

Zerefos’s team is now talking to the Tate museum in London about repeating the study with 40 paintings from the 20th century, to see whether artists have captured the effects of pollution on sunsets since the industrial revolution.


Big bangs

1783 -- Laki, Iceland. Volcanic eruption spread a sulphurous haze across western Europe, killing thousands.

1816 -- Tambora, Indonesia. Eruption killed 10,000 people directly and 66,000 due to starvation and disease during the “year without a summer” that followed, when temperatures plunged and harvests failed.

1883 -- Krakatoa, Indonesia. Loudest recorded bang in history. At least 36,417 people died. Average global temperatures dropped by 1.2 degrees Celsius.

1991 -- Pinatubo, Philippines. Killed 300 people. About 17 million tonnes of sulphur dioxide went into the atmosphere, reducing sunlight by 5% and global temperatures by 0.4 degrees Celsius.

 

Copyright Guardian News & Media Ltd 2007

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匿名 | Anonymous

未必

上述方法的可信度有待进一步证明,因为不同时期的画画技法有可能变化,并且不同人对真实色彩的捕捉程度不同,这有可能影响作品和真实场景的相似程度。

Unnecessarily

The reliability of the methods above needs further proof, because painting skills in different periods may change, and different people have different capturing levels of true colors , which may cause impact on the similarity of the works and the real scenes.

Default avatar
匿名 | Anonymous

历史美术和科学

C. Zerefos et al.研究小组对重新评审David Adam所撰写的文献, 是另一个应用历史美术在于科学研究方面具有价值的惯例。在此,我也附上了本身的网站,关于如何采纳历史美术的观点来探讨17世纪和18世纪期间珠江三角洲一带的环境变化。类似的分析对中国环境研究员会有所帮助。http://fas.org/china_lands/art.pdf

Historical art and science

David Adam's review of the paper by the research team of C. Zerefos et al. is another example showing the value of historical art for scientific studies. Included below is a web site of mine which shows how historical art was used to assess the state of the Pearl River Delta's environment during the 1700s and 1800s. Such analyses of this sort can be useful to China's environmental researchers.
http://fas.org/china_lands/art.pdf

Default avatar
匿名 | Anonymous

回评论2

让人惊奇的是不同时期不同流派的画作,以及不同的画家都相当精确地重现了红绿比例。这个结论是通过比较重大火山爆发事件后天空变红的程度得出的。我们找到的最高的红绿比例及独立估算的气载尘埃量均力证了伟大的艺术家们对颜色的真实比例进行了重现。我们相信我们所采用的比例考虑到了各种颜色的衰退,因为红和绿均会褪色,而据猜想,两种颜色衰退的速度是一样的。 泽勒福斯教授

Respond to comment No 2

It is amazing that regardless of different periods and different currents in art paintings and different artists reproduce the red to green ratios quite accurately. This was proven in the paper by comparing the reddening of the sky following major volcanic eruptions. The high correlation found from the red to green ratio and the independently estimated dust vail index strongly supports that great artists have presented the true ratios of colors. We believe that the ratios we used take care of any aging of the colours because red and green are "agecent" colours and the assumption is that they age with the same rate.

Christos Zerefos
Professor