A global warming primer

The Long Term history of temperature

On the long geological time scale there were major glaciations in the Quaternary, Permian, Eocambrian and at least five Precambrian glaciations. We are living in an interglacial in the Quaternary Glaciation, which itself has minor maxima and minima:

The main warming periods are: Egyptian (Old Kingdom), Minoan, Roman, Mediaeval (1000 – 1300), 20th Century. The main cold periods are: Dark ages, Little Ice Age 1300 to 1850 including the Maunder minimum 1645 to 1715 and the Dalton Minimum  790 to 1820.

We shall see later that these correspond to solar maxima and minima.

Central England has the longest record of thermometer readings, back to 1661. It shows the Little Ice Age, including the Dalton Minimum (the last time the River Thames froze over) and the even colder Maunder Minimum. The later years are affected by heat island effects.

Data from the rural US go back to 1893, and avoids heat islands. The hottest year was 1936.

SEA LEVEL

Sea level has been generally rising since the end of the last ice age. Based on tide gauge data a generally accepted rise is of about 1.5 mm per year since end of last glacial,

The European satellite, Evisat, provided the best available data. It showed falling sea level since it was launched in 2002, and for the last two years decline is continuing at 5mm/yr.

Unfortunately Evisat broke down on April 8^th 2012.

NASA also reported in 2011 "Global sea level this summer is a quarter inch lower (~6mm) than last summer".

Two particular places have been used to enhance the rising sea level scare, the coral islands of Tuvalu and the Maldives. Since they are close to sea level it was repeatedly claimed that they are in imminent danger. But Webb and Kench presented the first quantitative analysis of physical changes in 27 atoll islands in the SW Pacific (including Tuvalu) over a 19 to 61 year period. They found that 86% of islands remained stable (43%) or increased in area (43%).

Coral islands are increasing in size because coral grows: the reef is a living thing. Coupled with erosion and deposition the coast is modified, but there is no danger of drowning. The Maldives were studied by a team of geomorphologists led by the doyen of sea level studies, Niklas Axel-Morner, and they found no evidence of sea level rise.

Alarmists claim there will be a rise of several metres by the end of the century. Robin Williams, an Australian alarmist who runs the so-called Science Show on national radio, has even claimed 100 m.