some of what I left out about water & costs of removing CO2 re: the model
Water Vapour is the most abundant greenhouse gas in the atmosphere. More water vapour absorbs more thermal IR energy (heat) radiated from the Earth. That makes the atmosphere warmer with capacity to hold more water vapour—a positive feedback loop. Eventually water condenses and there are clouds that reflect some incoming sunshine. The hydrological cycle is expected to have a positive trend on global warming (more water vapour more warming, more warming more water vapour) but so far it hasn’t been well measured and tracked. General steps to prevent global warming are the only way it is addressed. Evolution of earth’s atmosphere: The initial hydrogen and helium escaped into space. Later an early atmosphere formed by outgassing. It was probably dominated by water vapour as is outgassing from volcanos today. There followed a deluge of rain creating rivers and ocean etc. Comets could have made a big contribution. Then nitrogen dominated and there was no oxygen. Photosynthetic life reduced the carbon dioxide content of the atmosphere, and also started to produce oxygen. By 2 billion years ago, there was enough oxygen to begin to support multicellular life. Oxygen increased in stages. Once sufficient oxygen had accumulated in the stratosphere, it was acted on by sunlight to form ozone. It was not until about 1 billion years ago that the reservoirs of oxidizable rock became saturated and the free oxygen stayed in the air becoming about 20% of the atmosphere. Currently water vapor varies between near zero to a few percent while Carbon dioxide has a concentration of about 350 ppm or 0.0350 percent. Some desserts are hot, some are cold—what all desserts are is arid—they lack water. Evaporation exceeds precipitation. Humidity—water vapor in the air—is near zero in most deserts. The largest desert in the world is also the coldest—Antartica. Rising temperatures have huge effects on fragile desert ecosystems. Increasing temperatures lead to the loss of nitrogen, an important nutrient, from the soil. Heat prevents microbes from converting nutrients to nitrates. Global warming means more rainfall in some places, less rainfall in others. Areas facing reduced precipitation include some of the largest deserts in the world: North Africa (Sahara), the American Southwest (Sonoran and Chihuahuan), the southern Andes (Patagonia), and western Australia (Great Victoria). Air temperatures and moisture conditions could become such that people outdoors could no longer cool by perspiration. In such circumstances no normal healthy person could survive more than six hours. A deadly heat wave killed 93 people in Quebec last year without reaching that extreme. A Silicon Valley venture capital firm, Y Combinator proposed flooding a desert half as big as Sahara with 238 trillion gallons of desalinated ocean water and creating millions of reservoirs to grow enough algae to eat all Earth’s excess carbon dioxide. Y Combinator pegs the price tag at $50 trillion. That’s roughly half the entire globe’s economic productivity for a year. (Not to mention the lost habitat—deserts are not empty. And what about the add global warming by water evaporation and by building the infrastructure and transporting water etc.) Donna Y [email protected] . > On Jun 15, 2019, at 8:12 AM, Raul Miller <[email protected]> wrote: > > You left out water vapor. H2O is a more significant greenhouse gas > than CO2. (This is why temperatures are more extreme in deserts than > in coastal regions.) ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
