tmosp keeps us  it, Eartemperature of minus 60 degrees Fa. In addition,tmosps incoming sraviolet rays, and togetmospto a fifteen-foot tective concrete, and  it tors fromspace iny daggers. Even raindrops  for tmosphere’s slowing drag.

    t striking t our atmosp t very muc. It extendsup 120 miles, eous andard desktop globe it  ts of varnish.

    For scientific convenience, tmospo four unequal layers: tropospratospen called troposp t’s dear to us. It alone contains enougo alloo function, t sly becomes uncongenial to life as you climb up t.

    From ground level to its  point, tropospurning sp ten milest tor and no more temperate latitudes mospually all ter, and tually all tained mucween you and oblivion.

    Beyond tropospratospop of a storm cloudflattening out into t tropospratospropopause and . Pause int mean to stop momentarily but to cease altoget’s from t as menopause. Even at its greatest extent, tropopause is not very distant. A fastelevator of t used in modern skyscrapers could get you t ty minutes,t to make trip. Suc pressurization  t, result in severe cerebral and pulmonary edemas, adangerous excess of fluids in tissues.  tform, anyone inside  certainly be dead or dying. Even a more measuredascent  deal of discomfort. temperature six miles up canbe -70 degrees Fa, and you  least very muce,supplementary oxygen.

    After you  tropospemperature soon o about 40degrees Fa, to tive effects of ozone (sometdiscovered on ). It to as loing to 2,700 degrees Fa or more in tly namedbut very erratic temperatures can vary by a to nig must be said t “temperature” at suc becomes a someional concept. temperature is really just a measure of tivity of molecules. At sealevel, air molecules are so t one molecule can move only tiniest distance—aboutto be precise—before banging into anotrillions ofmolecules are constantly colliding, a lot of  gets exc at t of t fifty miles or more, t any t and act. So alteractions bettle  transference. tellitesand spaces  any man-made objectorbiting at t level  into flame.

    Even so, spaceso take care in ter atmospicularly on return trips toEarttle Columbia demonstrated all too tragically in February 2003.

    Altmosp comes in at too steep an angle—more t 6 degrees—or too sly it can strike enougo generate drag of anexceedingly combustible nature. Conversely, if an incoming ve ttoo s could o space, like a pebble skipped across er.

    But you needn’t venture to tmospo be reminded of ime in a lofty city  o rise too many t from sea level before your body begins toprotest. Even experienced mountaineers, s of fitness, training, and bottledoxygen, quickly become vulnerable at  to confusion, nausea, exion, frostbite,ite, and a great many otumbling dysfunctions. In aic s o it  designed to operateso far above sea level.

    “Even under t favorable circumstances,” ter ten ofconditions atop Everest, “every step at t altitude demands a colossal effort of  force yourself to make every movement, reacuallytened by a leaden, deadly fatigue.” In t, tisaineerand filmmaker Matt Dickinson records isionup Everest, “found o deater a piece of infected fles Somervell managed to cougruction. It turned out to be “tire mucus lining of his larynx.”

    Bodily distress is notorious above 25,000 feet—to climbers as t many people become severely debilitated, even dangerously ill, at s of nomore t or so. Susceptibility tle to do ness. Grannies sometimescaper about in lofty situations o il conveyed to loitudes.

    te limit of olerance for continuous living appears to be about 5,500meters, or 18,000 feet, but even people conditioned to living at altitude could not tolerate sucs for long. Frances As, in Life at tremes, notes t t 5,800 meters, but t to descend 460 meters eacinuously at t elevation. People  altitude en spent tionatelylarge cs and lungs, increasing ty of oxygen-bearing red blood cells by almost ats to and. Moreover, above 5,500 meters even t ed  provide agrous o bring it to its full term.

    In to make experimental balloon ascents in Europe,somet surprised t got as temperature drops about3 degrees Fa  you climb. Logic o indicate tt to a source of , t of tion ist you are not really getting nearer ty-to move a couple of t closer to it is like taking one stepcloser to a busralia o smell smoke.

    takes us back to tion of ty of molecules in tmosphere.

    Sunligoms. It increases te at e to one anot. ’s really excited atoms you feel. them.

    Air is deceptive stuff. Even at sea level, end to t  y of bulk, and t bulk often exerts itself. As a marinescientist named yville te more tury ago: “e sometimes find er, t nearly on ly piled upon us during t, but ion and buoyancy, since it requires a little less exertion to move our bodies in t feel crus extra on of pressure is t be crus is made mostly ofincompressible fluids, w.

    But get air in motion, as iff breeze, and you  it oget 5,200 million milliontons of air around us—25 million tons for every square mile of t—a notinconsequential volume.  millions of tons of atmosp at ty orforty miles an ’s  limbs snap and roof tiles go flying. As Antes, a typical  may consist of 750 million tons of cold air pinnedbeneatons of  is at timesmeteorologically exciting.

    Certainly tage of energy in torm, ited, can contain an amount of energy equivalent to four days’ use ofelectricity for ted States. In t conditions, storm clouds can rise to sof six to ten miles and contain updrafts and dos of one en side by side,   to fly ternalturmoil particles rical c entirelyunderstood ter particles tend to become positively co be ed by aircurrents to top of ticles linger at ting negativecively cicles o ruso tivelyco anyt gets in t of ligravels at270,000 miles an  t to a decidedly crisp 50,000 degreesFa, several times ter t any one moment 1,800torms are in progress around t across t every second about a ning bolts  the sky is a lively place.

    Muc goes on up t. Jet streams, usuallylocated about 30,000 to 35,000 feet up, can bo up to 180 miles an lyinfluence ems over s, yet tence  suspected untilpilots began to fly into t deal ofatmospood. A form of ion popularly knourbulence occasionally enlivens airplane flig ty sucs a yearare serious enougo need reporting. t associated ructures oranyt can be detected visually or by radar. t pockets of startlingturbulence in tranquil skies. In a typical incident, a plane en route fromSingapore to Sydney ral Australia in calm conditions —enougo fling unsecured people against twelve peoplewere injured, one seriously. No one knows w causes sucive cells of air.

    t moves air around in tmosp drives ternal engine of t, namely convection. Moist, orial regionsrises until it s tropopause and spreads out. As it travels aor and cools, it sinks.  s bottom, some of to fill and or, completing t.

    At tor tion process is generally stable and tably fair,but in temperate zones tterns are far more seasonal, localized, and random, tle betems of ems are created by rising air, o tually rain. arm air can ure tropical andsummer storms tend to be t. tend to be associated , itoften becomes manifest in tance, stratus clouds—tureless spra give us our overcast skies—ure-bearing updraftslack to break table air above, and instead spread out, likesmoke ting a ceiling. Indeed, if you cime, you can get a very goodidea of cte in a still room. Atfirst, it goes straigo impress anyone), and t spreads out in a diffused, est supercomputer in takingmeasurements in t carefully controlled environment, cannot tell you ake, so you can imagine ties t confront meteorologists o predict sucions in a spinning, windy, large-scale world.

    because  from tributed, differences inair pressure arise on t. Air can’t abide t rusrying to equalizetrying to keep to areas of lo; tank—and tently tpressured air s to get someplace else), and ter ter the wind blows.

    Incidentally,  t accumulate, groially, so a  ten times stronger tty miles an  a imes stronger—and  mucructive.

    Introduce several million tons of air to tor effect and t can be exceedinglyenergetic. A tropical y-four ion like Britain or France uses in a year.

    tmospo seek equilibrium  suspected by Edmonded upon in teentury by on George  rising and falling columns of air tended toproduce “cells” (kno in ter all, Englised a linkbetions of air t give us our trade tecave-Gaspard de Coriolis, ails of teractions in 1835, andt t. (Coriolis’s otinction at to introduceercoolers, ly.) t a brisk1,041 miles an  tor, toe slopes offconsiderably, to about 600 miles an ance. t . If you are on tor tocarry you quite a distance—about 40,000 kilometers—to get you back to t. If youstand beside travel only a fe to complete arevolution, yet in bot takes ty-four o get you back to where you began.

    t follo t to tor ter you must be spinning.

    t explains o tance, seem to curve to t in to t in t. tandard o envision to imagine yourself at ter of a large carousel and tossing a ball tosomeone positioned on time ts to ter, target personive, it looks as if it  is t, and it is ems tops. t is also  to left or rigeen miles e by about a o the sea.

    Considering tical and psycance of to nearly everyone,it’s surprising t meteorology didn’t really get going as a science until sly before turn of teentury (term meteorology itself  . Granger in a book of logic).

    Part of t successful meteorology requires t oftemperatures, and ters for a long time proved more difficult to make texpect. An accurate reading  on getting a very even bore in a glass tube, andt  easy to do. t person to crack t, aDutcruments, er in 1717. ed trument in a  put freezing at 32 degrees andboiling at 212 degrees. From tset tricity botronomer, came up ing scale. In proof of tion t inventors seldom get matters entirely rig zeroand freezing point 100 on  t was soon reversed.

    t frequently identified as teorology  teentury. ypes their names in 1803.

    Altive and respected member of ty and employedLinnaean principles in y as to announce em of classification. (ty,you may just recall from an earlier cer, ed to trous oxide, so ed ation tention it deserved. It is a point on ratus for tin), and cirrus (meaning “curled”) for tions t generally presage colder o tlyadded a fourterm, nimbus (from tin for “cloud”), for a rain cloud. ty ofem  ts could be freely recombined to describe everysratocumulus, cirrostratus, cumulocongestus, and so on. Ite , and not just in England. t Joaken em t ed four poems to howard.

    em o over t ttle read International Cloud Atlas runs to t interestingly virtually all t-ypes—mammatus, pileus, nebulosis, spissatus, floccus, and mediocris area sampling— on side meteorology and not terribly mucold. Incidentally, t, mucion of t atlas, produced in 1896,divided clouds into ten basic types, of  cushiony-looking wasnumber nine, cumulonimbus.

    1t seems to o be oncloud nine.”

    For all t and fury of torm cloud, tually a benign and surprisingly insubstantial to a side may contain no more ty-five or ty gallons of er—“about enougo fill a batrefil ed. You can get some sense of terial quality of clouds by strolling ter all, not lacks to fly. to quote trefil again: “If you ypicalfog, you o contact  er—not enougogive you a decent drink.” In consequence, clouds are not great reservoirs of er. Only about0.035 percent of ter is floating around above us at any moment.

    Depending on er molecule varies  lands infertile soil it s or reevaporated directly finds its o ter,  may not see sunlig gets really deep.  a lake, you are looking at acollection of molecules t  a decade. In time is t to be more like a oget 60 percent of1If you ruck by ifully crisp and end to be, in a cumulus cloud t interior of t. Any er molecule t strays beyond tely zapped by to keep its fine edge. Muc soclearly delineated, o be blurry at the edges.

    er molecules in a rainfall are returned to tmosped, the skybefore falling again as rain.

    Evaporation is a s process, as you can easily gauge by te of a puddle on asummer’s day. Even someterranean  in a t  continually replenis occurred a little under six millionyears ago and provoked o science as ty Crisis.  continental movement closed trait of Gibraltar. As terraneandried, its evaporated contents fell as freser rain into oting tiness—indeed, making t dilute enougo freeze over larger areas than normal.

    t and puso an iceage. So at least theory goes.

    is certainly true, as far as ell, is t a little c, as le furted us.

    Oceans are t’s surface beeorologistsincreasingly treat oceans and atmospem, tle of our attention er is marvelous at ransporting . Every day,tream carries an amount of  to Europe equivalent to tput of coalfor ten years, h Canadaand Russia.

    But er also est days. For t reason tends to be a lag in tronomical start of aseason and tual feeling t t season arted. So spring may officially start in t it doesn’t feel like it in most places until April at t.

    t one uniform mass of er. temperature, salinity,depty, and so on s on  around, s climate. tlantic, for instance, is saltier too. tier er is t is, and dense er sinks. it its extra burden of salt, tlantic currents o tic,  deprivingEurope of all t kindly  of  transfer on Eart is knoion, s far belo detected by tist-adventurer Count von Rumford in 1797.

    2  surface ers, as t to ty of Europe, groo greatdeptrip back to tarctica,t up in tarctic Circumpolar Current,  can take 1,500 years for er to travel from term means a number of to different people, it appears. In November 2002, Carl unscpublis in Science, quot; Is tion?,quot; in  to signify at least seven different pion at tion driven by differences in density or buoyancy, quot;meridional overturning circulation of mass,quot; and soon)-to do ions and transfer of , tiously vague and embracingsense in w here.

    Nortlantic to t t and er te is enormous.

    (As for tion of   takes a drop ofer to get from one ocean to anot scientists can measure compoundsin ter like c  in t of measurements from different deptions t ter’s movement.)tion not only moves  around, but also o stir up nutrients asts rise and fall, making greater volumes of table for fisures. Unfortunately, it appears tion may also be very sensitive toco computer simulations, even a modest dilution of tcontent—from increased melting of t, for instance—could disrupt trously.

    t favor for us. tremendous volumes of carbon andprovide a means for it to be safely locked aies of our solar system is tt 25 percent more brigem was young.

    ted in a muc AubreyManning  it, “tely catastropon t it appears t our world ed.”

    So able and cool?

    Life does. trillions upon trillions of tiny marine organisms t most of us ure atmosp falls as rain and use it (in combination o make tiny s frombeing reevaporated into tmosp iny foraminiferans and coccolito ttomof to limestone. It is remarkable, ural feature like te Cliffs of Dover in England, to reflect t it ismade up of not tiny deceased marine organisms, but even more remarkable er. A six-incain ers of compressed carbon dioxide t  all. Altoget ty times as mucmospually muc limestone urn to tmospo term carbon cycle. takes a verylong time—about ypical carbon atom—but in turbance it  keeping te stable.

    Unfortunately, ion for disrupting tting lots of extra carbon into tmosp ornot. Since 1850, it imated,  a ons of extracarbon into total t increases by about seven billion tons eac’snot actually all t mucure—mostly ts—sends about 200 billion tons of carbon dioxide into tmospy times as mucories. But you o look att ies to see ribution makes.

    e kno tural” level of carbon dioxide in tmosp is, before arted inflating it rial activity—is about 280 partsper million. By 1958, arted to pay attention to it, it o 315parts per million. today it is over 360 parts per million and rising by rouger of 1percent a year. By ty-first century it is forecast to rise to about 560 partsper million.

    So far, ts ( as Peter Cox of tiseorological Office puts it:

    “tical tural biospops buffering us from ts ofour emissions and actually starts to amplify t to adapt, many trees and ots ores of carbon and adding to tant past even  a ribution. t evenure is quite  is almost certain t eventually t itself and return to a situation of stability and  time t took a mere sixty thousand years.