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It is possible that a negative feedback cycle is responsible for the recent global warming ‘pause... more It is possible that a negative feedback cycle is responsible for the recent global warming ‘pause’ and will delay further warming for centuries. The only necessary assumption is that organisms with access to a free source of energy will take advantage of it. These are poikilothermic animals which migrate vertically across the ocean thermocline. The change in body temperature which results can be used to generate energy for the animal’s use, using internal chemical mechanisms whose efficiency is limited by the Carnot cycle. Even a small rise in surface temperature greatly increases the energy available to such animals, and will tend to increase their numbers and activity. A thermodynamically inevitable consequence is that increasing quantities of heat energy will be pumped down into the mid"depths, as is already observed to be happening. [1] Confirmation of the effect would support Jeremy England’s hypothesis [2] that life tends to dissipate energy available from the environment...
In principle, many animals could obtain significant metabolic energy direct from their environmen... more In principle, many animals could obtain significant metabolic energy direct from their environment, additional to that from food. Photosynthesis requires a large area of modified skin and imposes behavioural constraints: few animals are photosynthetic. An alternative is to use the Carnot cycle, exploiting temperature differences. The maximum efficiency with which work can be extracted is ~∆T/T, where terrestrially T~300 K: comparable to photosynthesis. For a cold blooded animal which moves frequently between environments at significantly different temperatures, this energy harvest could be substantial: its entire body can act as a thermal reservoir. The energy harvesting machinery might however be hard to spot, much as 'brown fat' in human adults was overlooked until recently. It could be based on any temperature-sensitive chemical equilibrium. In the temperate and tropical oceans, animals could gain Carnot cycle energy very easily as they swim up and down through the thermocline during diel vertical migration. In so doing, they would transfer significant heat from near-surface waters to the mid-depths. Such behavior would be increasingly favored as surface waters become warmer, as has recently occurred. This could conceivably have contributed to the recent 'pause' in the anthropogenic greenhouse effect. At the origin of life, diurnal thermal harvesting by non-motile organisms could evolve far more easily than photosynthesis, and might have preceded both photosynthesis and the use of external chemical energy.
A focusing eye acts as a high-performance retroreflector, potentially appearing millions of times... more A focusing eye acts as a high-performance retroreflector, potentially appearing millions of times brighter when illuminated from a distance than would a matte white surface of the same area. In particular an eye which either has a reflective tapetum near its focal plane, or is operating at f-number less than unity, returns around half of
It is possible that a negative feedback cycle is responsible for the recent global warming ‘pause... more It is possible that a negative feedback cycle is responsible for the recent global warming ‘pause’ and will delay further warming for centuries. The only necessary assumption is that organisms with access to a free source of energy will take advantage of it. These are poikilothermic animals which migrate vertically across the ocean thermocline. The change in body temperature which results can be used to generate energy for the animal’s use, using internal chemical mechanisms whose efficiency is limited by the Carnot cycle. Even a small rise in surface temperature greatly increases the energy available to such animals, and will tend to increase their numbers and activity. A thermodynamically inevitable consequence is that increasing quantities of heat energy will be pumped down into the mid"depths, as is already observed to be happening. [1] Confirmation of the effect would support Jeremy England’s hypothesis [2] that life tends to dissipate energy available from the environment...
In principle, many animals could obtain significant metabolic energy direct from their environmen... more In principle, many animals could obtain significant metabolic energy direct from their environment, additional to that from food. Photosynthesis requires a large area of modified skin and imposes behavioural constraints: few animals are photosynthetic. An alternative is to use the Carnot cycle, exploiting temperature differences. The maximum efficiency with which work can be extracted is ~∆T/T, where terrestrially T~300 K: comparable to photosynthesis. For a cold blooded animal which moves frequently between environments at significantly different temperatures, this energy harvest could be substantial: its entire body can act as a thermal reservoir. The energy harvesting machinery might however be hard to spot, much as 'brown fat' in human adults was overlooked until recently. It could be based on any temperature-sensitive chemical equilibrium. In the temperate and tropical oceans, animals could gain Carnot cycle energy very easily as they swim up and down through the thermocline during diel vertical migration. In so doing, they would transfer significant heat from near-surface waters to the mid-depths. Such behavior would be increasingly favored as surface waters become warmer, as has recently occurred. This could conceivably have contributed to the recent 'pause' in the anthropogenic greenhouse effect. At the origin of life, diurnal thermal harvesting by non-motile organisms could evolve far more easily than photosynthesis, and might have preceded both photosynthesis and the use of external chemical energy.
A focusing eye acts as a high-performance retroreflector, potentially appearing millions of times... more A focusing eye acts as a high-performance retroreflector, potentially appearing millions of times brighter when illuminated from a distance than would a matte white surface of the same area. In particular an eye which either has a reflective tapetum near its focal plane, or is operating at f-number less than unity, returns around half of