Mini Era Glacial? O que esperar do futuro próximo

 
A única coisa que podemos dizer com absolutamente certeza é que não temos certeza de nada quando o assunto é o clima futuro.

Entre os anos de 1300 e 1850 o mundo conheceu a Mini Era Glacial, que foi amplificada entre 1645 e 1715. Nestes 70 anos o Sol atravessou o que se convencionou chamar de Mínimo de Maunder (gráfico): uma fase caracterizada pelo quase desaparecimento das manchas solares.


Antes da Mini Era Glacial os astrônomos contavam milhares de manchas solares (de 40.000 a 50.000 em um único ano), mas após o ano de 1645 elas praticamente desapareceram. Neste período em um ano eram visualizadas pouco mais de 50 manchas solares.

Incrível, mas mais incrível ainda foi o efeito devastador que esse fase de baixa atividade magnética solar teve sobre a Terra. Foi a última Mini Era do Gelo, cujo ápice durou quase 100 anos e destruiu economias, arrasou colheitas e até o transporte fluvial (muitos rios e lagos congelaram). O mar Báltico congelou e o transporte entre a Finlândia e a Groenlândia com o resto do mundo foi praticamente inviabilizado. Os glaciais das Alpes invadiram cidades e fazendas matando e destruindo.

Com o frio veio o colapso das plantações e, neste período, milhões de pessoas morreram de fome e de doenças, principalmente na Europa.

Em 1696 1/3 da população da Finlândia morreu de fome.

Tudo isso ocorreu com uma temperatura média de apenas dois graus centígrados abaixo das atuais...

Gradativamente as manchas solares reapareceram, atingindo o Máximo entre os anos de 1950 e 2000 (veja o gráfico). O Mundo havia voltado ao normal.

Mas, nestas últimas décadas os cientistas vem observando, preocupados, o decréscimo das manchas solares. Se torna óbvio, pelos gráficos do NOAA (veja), que o Solar Maximum já foi ultrapassado e que em pouco tempo as manchas solares irão praticamente desaparecer...mais uma vez.

Já em 2009 Bill Livingston do NOS havia previsto, através das medições do magnetismo solar (ele percebeu que os campos magnéticos decaiam a 50 gauss por ano), que em 2015 as manchas deveriam desaparecer iniciando mais uma Mini Era Glacial.

Ele errou!

As manchas desapareceram somente agora, em 2016.

Hoje faz uma semana que o Sol parece uma bola de bilhar amarela, sem manchas, assim como todos os gráficos estavam prevendo.
Segundo Livingston as manchas só aparecem quando o campo magnético solar está acima de 1.500 gauss, um limiar que tudo leva a crer foi atingido a uma semana atrás...

A partir deste ponto tudo é pura especulação.

Será que as manchas solares voltarão e um novo ciclo será reiniciado ou será que estamos, realmente, no início de uma nova Mini Era Glacial e que teremos uma repetição do fenômeno que afetou o mundo entre 1645 e 1815?

No gráfico das temperaturas (acima) feito pelo climatologista Cliff Harris dos últimos 4.416 anos é possível ver com precisão a alternância cíclica entre as mini eras de resfriamento e as mini eras de aquecimento global, sempre relacionadas a temperatura média de 57,1 graus Fahrenheit (12,5 graus centígrados).

A cada ciclo as fases de resfriamento se tornam mais longas e mais frias. A última foi a Mini Era Glacial entre 1300 e 1800.

Se estivermos adentrando um período de resfriamento global, como tudo indica, é hora de planejar.

Um novo hiato implicará, mais uma vez, em invernos extremos na Europa e na América do Norte e Ásia, onde, por coincidência estão as maiores economias e as maiores concentrações populacionais.

Não é preciso ser um vidente para entender os possíveis desdobramentos: o mundo pode entrar em um período de décadas de problemas relacionados ao frio.

Veremos a volta da mineração do carvão, que hoje se encontra praticamente banido dos radares dos mineradores. Com a necessidade de aquecimento os preços dos hidrocarbonetos irão subir viabilizando os jazimentos dos oil sands do Canadá. Projetos de energia limpa serão, possivelmente, engavetados.

Com a queda na produção agrícola no norte os países como o Brasil, pouco afetado pelas mudanças climáticas, se tornarão gigantescos produtores de grãos e demais commodities agrícolas.

Vai ser um tempo para tirar o casaco e as luvas do armário, sonhar com o efeito estufa e se preparar para uma mudança radical.

Se você gosta de esquiar não vai precisar voar para o hemisfério norte...

Tanzanite

Its range of lavender-blue colors make tanzanite unique in the gem world, creating a wonderful addition to the designer's gemstone palette.  Tanzanite's color has been compared to the color of Elizabeth Taylor's famous lavender eyes.  As a rule, the larger the tanzanite, thedeeper the color.  Very rarely, tanzanite is found in shades of yellow, green and pink.  Estimates are that the entire known source of tanzanite will dry up in fifteen to twenty years. The dusty frontier town of Arusha, in the northern part of Tanzania is located on a plateau in the Great Rift Valley amidst the Serengeti Plain, Nogorongoro Crater, Lake Manyara, Olduvai Gorge and Mt. Kilimanjaro National Parks. The closest 'major' city to the tanzanite mines of Merelani, Arusha is the world center for tanzanite brokers, sellers and buyers. Arusha is also where the International Criminal Tribunal for Rwanda is based.  Living and working conditions areharsh for Tanzanian miners. Merelani mine pits can flood in the rainy season, the miners' shacks are no more than corrugated aluminum and branches, and some shacks hold explosives used in mining, creating even more danger for miners.

the 'one source' wonder Tanzanite is a gem variety of zoisite that is strongly pleochroic, showing shades of either purple, blue, or slate gray, depending on which way the stone is turned. rough tanzanite While tanzanite's most desirable color as a 'gemmy' stone (to be set) is a deep blue to violet-blue, the stone also frequently comes in shades of lavender, lilac and periwinkle blue. Surprisingly, almost all tanzanite comes out of the ground a gray to root beer brown color. Although some stones found on the surface are purple-blue because of the heat of the equatorial sun, most tanzanite -- like many other gems -- is heat-treated to bring out the deeper, more desirable violet-blue color. This 'artificial' process merely continues the organic color treatment that tanzanite underwent millions of years ago while still under ground. Tanzanite is found almost entirely in Tanzania. Millions of years ago, metamorphous slates, gneiss stone and quartzites shaped impressive flat insular mountains, now known as the Merelani Hills on the wide planes near Mount Kilimanjaro and Tanzania's border with Kenya. It is in the core of these unusual rises that tanzanite is mined. independent miners in merelani, tanzania  photo: professional jeweler Tanzania remains the primary commercial source of tanzanite, a condition seen as both a blessing and a curse. This is because the supply of 'one locality' stones like tanzanite is particularly vulnerable: the deposit can run out (as was the rumor about tanzanite a few years ago) or the volatile politics of the area can interrupt the flow of stones for indefinite periods (also driving up prices). For instance, in 1998, supplies ground to a halt due to flooding, while cave-ins took many lives and security breaches at the mine sites escalated. Very small deposits of tanzanite have been found in Kenya, but have not been considered large enough for commercial purposes until recently. With tanzanite's ongoing popularity even these small deposits are now being mined.

chrysoprase

One of the rarest of the chalcedonies,chrysoprase is considered to be the most valuable. A lot of commercial chrysoprase ischalcedony artificially stained by impregnation with a green salt of nickel. Known to fade in prolonged exposure to sun, chrysoprase's resulting colorcan easily be confused with or passed off as fine jade.  Nickel Mountain was the last operatingmetal mine in Oregon, due to declining worldwide nickel prices through the1990�s.  Mined largely by hand, thin layers of the saprolite clay in which it is found arestripped away by bulldozers or other heavy equipment, after which thegemstone itself is collected by hand toprevent damage.  In 1991, at the International Gemological Symposium, Brisbane gemologist Grahame Brown estimated that Australiahas sufficient deposits to supply the world for another 20-40 years.

golden leek or granny smith? carved chrysoprase koalas photo: gem exotica Although its Greek name meaning "golden leek," denotes a golden yellow color, chryoprase is actually a beautiful translucent apple-green color, similar to Granny Smith apples. Formed by the weatherization of serpentine, chrysoprase occurs as fillings in cavities in serpentine. As the elements break down the serpentine, nickel, silica and other iron oxides are dissolved out of the stone and collect in cracks, crevices and saprolite (a soft, rich clay) in the underlying environment. chrysoprase mine, marlborough, queensland Australia currently has the worlds largest deposits of quality chrysoprase, estimated to be about 85% of world supply; it also has a pale lime variety known aslemon chrysoprase. Deposits are found in the Marlborough district of central Queensland, at Mount Davies in the remote northwest of South Australia, and at Wingelina and Yerilla in Western Australia. Queensland's chrysoprase is the most water-retentive, and therefore, the least prone to color fade or cracking. The gem is also found to a limited extent at Revdinsk, near Ekaterinburg, in the Russian Urals, as well as in India. The US has several locations -- most notably at Nickel Mountain, near the small town of Riddle in Douglas County, Oregon (in the southwest part of the state) -- where it occurs in nickeliferous serpentine.

Natural citrine

Citrine is considered to be the most valuable quartz gem.  Natural citrine's pale yellow color is due to the presence of ferric iron. All heat-treated material has at least a hint of red tint, whereas natural specimens do not. Because heat is used to affect the color of most citrines, care should be takennot to leave citrine jewelry in sunlight for very long.

various colors of citrine 'plates' ready for sale photo: silvestre 'garimpo' Natural citrine is a rare form of quartz crystal found in amethyst deposits. Many natural citrines may have started out as amethyst but heat from nearby magmatic forces caused the change to citrine. However, most citrines on the market today are heat treated amethyst or smokey quartz, cooked at high temperatures to produce the orange-yellow colors currently in demand. Many citrine as well as amethyst mines are near the equator, including those in Brazil, currently the world's largest producer of heat-treated citrine (from amethyst). Due to operational costs, lack of electricity, or the expense and time to procure an electric or gas oven in Brazil's remote mining areas, the preferable method of heat-treating is often to bury the brownish (low grade) amethyst in the soil, cooking it with sunlight.

Aquamarine is the green to blue-green

Aquamarine, heliodor, emerald,goshenite and morganite are allmembers of the beryl family.  Beryl is an important source of theelement beryllium , a metal with a variety of modern commercial uses, particularly in manufacturing metal alloys. Unlike emerald, aquamarine gems are often completely flawless. However,inclusions may include mica, hematiteand liquid-filled (often salt-water)' tubes.' The largest gem quality aquamarineon record was found in Brazil in 1910 andweighed 243 lbs. A thirteen-pound uncut piece resides in the American Museum of Natural History.  By one account, when Russia andAfghanistan were at war, Afghanis, locating a probable aquamarine deposit, would pitch a tent over the area, making it an inviting target for the Russians to bomb -- thereby eliminating days, if not weeks, of digging.

shades of green and blue aquamarine crystal Aquamarine is the green to blue-green to aqua variety of the mineral beryl (from the Greek berullos, meaning any "crystal"). It isdichroic, appearing with color and without when viewed from different angles. Most gem beryl comes from a very coarse-grained rock that geologists call pegmatite, a form of igneous rock consisting of extremely coarse granite resulting from the crystallization of magma rich in rare elements. Aquamarine is colored by trace amounts of iron that find their way into the crystal structure. However, the majority of gem aquamarines on the market today have been heat treated -- by heating them in an electric furnace to 842� F (450� C) -- to produce the popular sky blue, dark blue, and blue-green colors from less desirable yellow or pale stones. photo: garimpo talhado minea, brazil Brazil is a major supplier of aquamarines where they are mined around Teofilo Otoni in the western part of the state of Minas Gerais. Pakistan and Afghanistan also have significant deposits, but given the political contretemps between Pakistan and India, the recent years of war between Russia and Afghanistan, and the presence of al-Qaeda and the Taliban, mining activity has been sporadic, at best, and getting product out of the countries difficult. Russia mines aquamarine in several areas, most notably the Urals, Transbaikalia (east of Lake Baikal), and Siberia. Several African nations such as Nigeria and Madagascar mine the gem. In the US, Colorado and North Carolina have deposits.