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Global Warming The problem of scale. The imperceptible and the vast (1). As human beings we can judge: temperatures close to ‘normal’ weights in the range a few grammes to a hundred kilogrammes distances . from a few kilometres to less than a millimetre times
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The imperceptible and the vast (1) As human beings we can judge: • temperatures • close to ‘normal’ • weights • in the range a few grammes to a hundred kilogrammes • distances. • from a few kilometres to less than a millimetre • times • from a fraction of a second to periods of a few years.
The imperceptible and the vast (2) As human beings we cannot judge: • temperatures • more a few degrees away from ‘normal’ • weights • beyond a few tonnes or less than a gramme • distances • beyond a few kilometres or much less than a millimetre. • times. • much less than a second or greater than a fraction of a lifetime
The imperceptible and the vast (3) Quantities and qualities that extend beyond our range of familiarity seem either: imperceptible or vast • It is important to retain an ability to quantitatively assess quantities we perceive as imperceptible or vast • Becoming familiar is an important part of understanding • But then we can become too familiar!
The Planet Earth Diameter: 12,800 km Deepest hole: 10 km Atmosphere: Scale Height 8.4 km
The Sun Earth Diameter: 1,390,800 km
Powers of Ten 1 1018 1024 10-18 10-12 1030 1036 Very Very Small Very Very Large 10-15 10-9 1021 1027 1033 100 0.000001 10-6 1000000 106 1012 10-3 0.001 1000 103 109 1015
Powers of Ten 1 metre 1000000000000 m 0.000000000001 m 10-18 10-12 1012 Very Very Small Very Very Large 10-15 10-9 1018 1024 10-6 106 1012 1030 1036 10-3 103 109 1015 1021 1027 1033
Powers of Ten (Global Warming)Length scale in metres Distance to the Sun Diameter of the Earth Microbes Human Relationships 1018 1024 10-18 10-12 10-6 100 106 1012 1030 1036 Very Very Small Very Very Large 10-15 10-9 10-3 103 109 1015 1021 1027 1033 The phenomenon of global warming involves physical processes with length scales spanning 20 powers of 10! Tallest Mountain Deepest Trench Atoms & Molecules
Powers of Ten (time)Time scale in seconds Electoral Cycle 1 Year the Earth moves once around the Sun Deep Ocean Current Circulation time Time for a molecule to jiggle 1 second 1018 1024 10-18 10-12 10-6 100 106 1012 Milankovitch Cycles Very Very short Very Very Long 10-15 10-9 10-3 103 109 1015 1021 Age of the Earth A human lifetime The phenomenon of global warming involves physical processes with time scales spanning 25 powers of 10! Typical survival time of a civilisation End of last ice age