70% or less of the sunlight shining onto the Earth reaches the surface and is absorbed by the biosphere. From this absorbed energy, in combination with the presence of water and organic material, all life springs. The oceans, which cover 70.2% of the Earth’s surface and comprise 99.4% of the biosphere’s mass, form the great “heat battery” of the planetary surface. All weather and climate are generated from the heat glow of that battery. A portion of that heat glow, equivalent to the solar energy absorbed, must escape into space for the planetary surface to remain in heat balance, at a constant average temperature. For that temperature being 15°C (59°F), 62.31% of the heat glow must escape.
30% or more of the incident solar energy is reflected back into space, with 24% of that reflection by clouds, and 6% of that reflection from land and ocean surfaces. While snow and ice are the most nearly perfect reflective of such surfaces, they only cover 10% to 11% of the planet and that coverage is slowly being reduced by global warming, increasing the solar heating.
Our introduction of greenhouse gases and pollution particles into the atmosphere has added to the already existing load of naturally emitted humidity, organic vapors and grit from volcanic eruptions and windblown dust. These components of the atmosphere absorb and retain heat (infrared radiation), blocking some of the necessary heat glow loss, and thus warming the planet. The increasing accumulation of these components — because a warmer world has higher humidity producing more clouds, and because of our continuing emission of atmospheric pollutants — scatter an increasing portion of the incoming sunlight back into space, which is a cooling effect called “global dimming.” The imbalance of all these effects is dominated by warming and the biosphere’s temperature is rising at an accelerating rate.
My life is a race against the clock of a certain though indeterminate finality. The COVID-19 pandemic has made me very conscious of this inevitability. After seven decades of existence I cannot do everything I want, in terms of living, fast enough. This is not irrational terror, it is awakened appreciation and understanding. There is all of Shelley yet to read, and Keats, and so many more; and so many more birds and flowers, and daylight and nighttime beauties of the Nature to see, and so many more differential equations and physical problems to solve, to not want to go on living. The urge for continuation is innate, genetically programmed, whether in robotic virus particles or in cognitive life forms like cats and human beings. For me, that cognition includes the irrational emotional desire to combat global warming so that future generations of all Earth’s life forms have decent chances of continuing.