Tag Archives: Earth

Ocean Climate

Ocean acidification is the ongoing decrease in the pH of the Earth‘s oceans, caused by the uptake of carbon dioxide (CO2) from the atmosphere.[2] Seawater is slightly basic (meaning pH > 7), and the process in question is a shift towards pH-neutral conditions rather than a transition to acidic conditions (pH < 7).[3] Ocean alkalinity is not changed by the process, or may increase over long time periods due to carbonate dissolution.[4] An estimated 30–40% of the carbon dioxide from human activity released into the atmosphere dissolves into oceans, rivers and lakes.[5][6] To achieve chemical equilibrium, some of it reacts with the water to form carbonic acid. Some of these extra carbonic acid molecules react with a water molecule to give a bicarbonate ion and a hydronium ion, thus increasing ocean acidity (H+ ion concentration). Between 1751 and 1994 surface ocean pH is estimated to have decreased from approximately 8.25 to 8.14,[7] representing an increase of almost 30% in H+ion concentration in the world’s oceans.[8][9] Earth System Models project that within the last decade ocean acidity exceeded historical analogs[10] and in combination with other ocean biogeochemical changes could undermine the functioning of marine ecosystems and disrupt the provision of many goods and services associated with the ocean.[11]

Increasing acidity is thought to have a range of potentially harmful consequences for marine organisms, such as depressing metabolic rates and immune responses in some organisms, and causing coral bleaching.[citation needed] By increasing the presence of free hydrogen ions, each molecule of carbonic acid that forms in the oceans ultimately results in the conversion of two carbonate ions into bicarbonate ions. This net decrease in the amount of carbonate ions available makes it more difficult for marine calcifying organisms, such as coral and some plankton, to form biogenic calcium carbonate, and such structures become vulnerable to dissolution.[12] Ongoing acidification of the oceans threatens food chains connected with the oceans.[13][14] As members of theInterAcademy Panel, 105 science academies have issued a statement on ocean acidification recommending that by 2050, global CO2emissions be reduced by at least 50% compared to the 1990 level.[15]

While ongoing ocean acidification is anthropogenic in origin, it has occurred previously in Earth’s history.[16] The most notable example is the Paleocene-Eocene Thermal Maximum (PETM),[17] which occurred approximately 56 million years ago. For reasons that are currently uncertain, massive amounts of carbon entered the ocean and atmosphere, and led to the dissolution of carbonate sediments in all ocean basins.

Ocean acidification has been called the “evil twin of global warming[18][19][20][21][22] and “the other CO2 problem”.[19][21][23]

SHIFTING BASELINES AND DYING OCEANS

by DONALD PROTHERO on Dec 19 2012

Climate deniers try to distort or obfuscate the evidence about the changing atmosphere, and it’s not always easy to give overwhelmingly conclusive data that would convince them. In some cases the data are tricky to analyze, or do not have well-documented long-term histories necessary to answer every concern about whether recent weather events are truly unprecedented. The atmospheric system is very complicated, with many different processes operating on short-term, medium-term, and long-term time scales, and not all of it is as well understood as we would like. Thus, the arguments over changes in earth’s atmosphere often reach an impasse.

Not so for the oceans. Although oceans are an even larger system than the atmosphere, we understand them much better. More importantly, we have an excellent long-term record of how the oceans have changed over millions of years from thousands of deep-sea cores, and from the paleontological record of marine fossils that goes back over 700 million years. And unlike the atmospheres, oceans change very slowly over time, since the thermal inertia of water makes the seas very resistant to change except on long-term time scales. In addition, most ocean currents move slowly compared to atmospheric currents. So no matter what you want to make of the data showing atmospheric change, the changes in the oceans are more alarming, since oceans require immense stimuli to cause such change.

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DinosaurTheory.com

Does size matter? More specifically, can a rock, a person, a car, a planet, an airplane, or a dinosaur exist at any arbitrary size? This is a fundamental scientific question, and yet for the most part the science community has sidestepped this simple question. Since the science community has not clarified why animals cannot be any size, science fiction writers have had fun playing with the idea that animals can be many times larger or many times smaller than their normal size. While many of us may enjoy the entertaining movies showing people or other animals the wrong size, this is not helping to clarify to the public that size really does matter. Galileo’s Square-Cube Law explains why size matters, and in fact Galileo’s Square-Cube Law is such a fundamental scientific truth that science is hardly science without it.

Year after year we watch science fiction movies showing creatures that are the wrong size. We may wonder what is wrong with this picture; what, if anything, limits the size of animals. But since Galileo’s Square-Cube Law was not included in our elementary science education most people fail to recognize that size matters.

Venus

Venus, Mars and Earth, three out of the four inner or ‘rocky’ planets of the Solar System, have a lot in common – a solid surface you could walk on, a comparable surface composition, an atmosphere and a weather system.

If you are looking for a twin sister to Earth, that would be Venus… or is it?

 Venus Earth
Mass 4.87 x 1024 kg 5.98 x 1024 kg
Radius 6052 km 6378 km
Density 5250 kg/m3 5520 kg/m3
Av. distance from Sun 108 million km 150 million km
Rotation period (day) 243 Earth days (retrograde) 23 hours 56 minutes
Orbit period (year) 224.7 Earth days 365.2 days
Surface temp. (mean) 465 °C 15 °C
Surface pressure 90 bar 1 bar (sea level)
Albedo (reflectivity) 0.76 0.37
Highest point on surface Maxwell Montes
(17 km)
Mount Everest
(8.8 km)
Atmosphere 96% CO2 , 3% N2 78% N2 , 21% O2, 1% Ar
Surface composition Basalt rock, altered materials Basalt, granite, altered materials
Orbit inclination 3.4° 0° by definition
Obliquity of axis 178° 23.5°
Surface gravity (equator) 8.9 m/s2 9.8 m/s2
Moons None 1 (The Moon)

safe operating space

Footprint Calculator

How much land area does it take to support your lifestyle? Take this quiz to find out your Ecological Footprint, discover your biggest areas of resource consumption, and learn what you can do to tread more lightly on the earth.

There are limits to the individual’s ability to instigate major change on the Earth’s changing conditions. Many people indicated that, even after dramatically changing certain behaviors such as fuel usage, their scores were marginally changed (if at all) – and depending on which country you reside in, a certain allotment of environmental impact is prescribed via goods and services. Therefore, to reduce this allotment, collective action (through aggressive campaigning or swift policy changes) must take priority.

Of course, this is not to say that individual actions do not matter – indeed, collectivity is comprised of a large group of individuals. By committing to invest in solar rather than non-renewable energy sources or eliminating meat from your diet to reduce the amount of grains that must be grown to feed those animals or reducing time in the shower, you are advocating for the Earth and setting an example that others can follow.

At the rate things are going, the Earth in the coming decades could cease to be a “safe operating space” for human beings. That is the conclusion of a new paper published Thursday in the journal Science by 18 researchers trying to gauge the breaking points in the natural world.

Nine planetary boundaries
1. Climate change
2. Change in biosphere integrity (biodiversity loss and species extinction)
3. Stratospheric ozone depletion
4. Ocean acidification
5. Biogeochemical flows (phosphorus and nitrogen cycles)
6. Land-system change (for example deforestation)
7. Freshwater use
8. Atmospheric aerosol loading (microscopic particles in the atmosphere that affect climate and living organisms)
9. Introduction of novel entities (e.g. organic pollutants, radioactive materials, nanomaterials, and micro-plastics).

Prepared by researchers at the Stockholm Resilience Centre, the study looks specifically at how “four of nine planetary boundaries have now been crossed as a result of human activity.” Published in the journalScience* on Thursday, the 18 researchers involved with compiling evidence for the report—titled ‘Planetary Boundaries 2.0‘—found that when it comes to climate change, species extinction and biodiversity loss, deforestation and other land-system changes, and altered biogeochemical cycles (such as changes to how key organic compounds like phosphorus and nitrogen are operating in the environment), the degradation that has already take place is driving the Earth System, as a whole, into a new state of imbalance.

The conclusion that the world’s dominant economic model—a globalized form of neoliberal capitalism, largely based on international trade and fueled by extracting and consuming natural resources—is the driving force behind planetary destruction will not come as a shock, but the model’s detailed description of how this has worked since the middle of the 20th century makes a more substantial case than many previous attempts.

“When we first aggregated these datasets, we expected to see major changes but what surprised us was the timing. Almost all graphs show the same pattern. The most dramatic shifts have occurred since 1950. We can say that around 1950 was the start of the Great Acceleration,” says Steffen. “After 1950 we can see that major Earth System changes became directly linked to changes largely related to the global economic system. This is a new phenomenon and indicates that humanity has a new responsibility at a global level for the planet.”

Resources

Holocene

The Holocene /ˈhɒlɵsn/ is a geological epoch which began at the end of the Pleistocene[1] (at 11,700 calendar years BP)[2] and continues to the present. The Holocene is part of the Quaternary period. Its name comes from the Greek words ὅλος (holos, whole or entire) and καινός (kainos, new), meaning “entirely recent”.[3] It has been identified with the current warm period, known as MIS 1, and can be considered an interglacial in the current ice age based on that evidence.

The Holocene also encompasses the growth and impacts of the human species worldwide, including all its written history, development of major civilizations, and overall significant transition toward urban living in the present. Human impacts of the modern era on the Earth and its ecosystems may be considered of global significance for future evolution of living species, including approximately synchronous lithospheric evidence, or more recently atmospheric evidence of human impacts. Given these, a new term Anthropocene, is specifically proposed and used informally only for the very latest part of modern history and of significant human impact since the epoch of the Neolithic Revolution (around 12,000 years BP).

It is accepted by the International Commission on Stratigraphy that the Holocene started approximately 11,700 years BP (before present).[2] The epoch follows the Pleistocene and the last glacial period (local names for the last glacial period include the Wisconsinan in North America,[4] the Weichselian in Europe,[5] the Devensian in the United Kingdom,[6] the Llanquihue in Chile [7] and the Otiran in New Zealand[8]). The Holocene can be subdivided into five time intervals, or chronozones, based on climatic fluctuations:[9]

Note: “ka” means “thousand years” (non-calibrated C14 dates)

The Blytt-Sernander classification of climatic periods defined, initially, by plant remains in peat mosses, is now being explored currently by geologists working in different regions studying sea levels, peat bogs and ice core samples by a variety of methods, with a view toward further verifying and refining the Blytt-Sernander sequence. They find a general correspondence across Eurasia and North America, though the method was once thought to be of no interest. The scheme was defined for Northern Europe, but the climate changes were claimed to occur more widely. The periods of the scheme include a few of the final pre-Holocene oscillations of the last glacial period and then classify climates of more recent prehistory.

Paleontologists have defined no faunal stages for the Holocene. If subdivision is necessary, periods of human technological development, such as the Mesolithic, Neolithic, and Bronze Age, are usually used. However, the time periods referenced by these terms vary with the emergence of those technologies in different parts of the world.

Climatically, the Holocene may be divided evenly into the Hypsithermal and Neoglacial periods; the boundary coincides with the start of the Bronze Age in European civilization. According to some scholars, a third division, the Anthropocene, began in the 18th century.[10]

Continental motions due to plate tectonics are less than a kilometer over a span of only 10,000 years. However, ice melt caused world sea levels to rise about 35 m (115 ft) in the early part of the Holocene. In addition, many areas above about 40 degrees north latitude had been depressed by the weight of the Pleistocene glaciers and rose as much as 180 m (590 ft) due to post-glacial rebound over the late Pleistocene and Holocene, and are still rising today.[11]

The sea level rise and temporary land depression allowed temporary marine incursions into areas that are now far from the sea. Holocene marine fossils are known from Vermont, Quebec, Ontario, Maine, New Hampshire, and Michigan. Other than higher-latitude temporary marine incursions associated with glacial depression, Holocene fossils are found primarily in lakebed, floodplain, and cave deposits. Holocene marine deposits along low-latitude coastlines are rare because the rise in sea levels during the period exceeds any likely tectonic uplift of non-glacial origin.

Post-glacial rebound in the Scandinavia region resulted in the formation of the Baltic Sea. The region continues to rise, still causing weak earthquakes across Northern Europe. The equivalent event in North America was the rebound of Hudson Bay, as it shrank from its larger, immediate post-glacial Tyrrell Sea phase, to near its present boundaries.

Climate has been fairly stable over the Holocene. Ice core records show that before the Holocene there was global warming after the end of the last ice age and cooling periods, but climate changes became more regional at the start of the Younger Dryas. During the transition from last glacial to holocene, the Huelmo/Mascardi Cold Reversal in the Southern Hemisphere began before the Younger Dryas, and the maximum warmth flowed south to north from 11,000 to 7,000 years ago. It appears that this was influenced by the residual glacial ice remaining in the Northern Hemisphere until the later date.

The hypsithermal was a period of warming in which the global climate became warmer. However, the warming was probably not uniform across the world. This period of warmth ended about 5,500 years ago with the descent into the Neoglacial. At that time, the climate was not unlike today’s, but there was a slightly warmer period from the 10th–14th centuries known as the Medieval Warm Period. This was followed by the Little Ice Age, from the 13th or 14th century to the mid 19th century, which was a period of significant cooling, though not everywhere as severe as previous times during neoglaciation.

The Holocene warming is an interglacial period and there is no reason to believe that it represents a permanent end to the current ice age. However, the current global warming may result in the Earth becoming warmer than the Eemian Stage, which peaked at roughly 125,000 years ago and was warmer than the Holocene. This prediction is sometimes referred to as a super-interglacial.

Compared to glacial conditions, habitable zones have expanded northwards, reaching their northernmost point during the hypsithermal. Greater moisture in the polar regions has caused the disappearance of steppe-tundra.

The temporal and spatial extent of Holocene climate change is an area of considerable uncertainty, with solar forcing recently proposed to be the origin of cycles identified in the North Atlantic region. Climate cyclicity through the Holocene (Bond events) has been observed in or near marine settings and is strongly controlled by glacial input to the North Atlantic.[12][13] Periodicities of ~2500, ~1500, and ~1000 years are generally observed in the North Atlantic.[14][15][16] At the same time spectral analyses of the continental record, which is remote from oceanic influence, reveal persistent periodicities of 1000 and 500 years that may correspond to solar activity variations during the Holocene epoch.[17]A 1500 year cycle corresponding to the North Atlantic oceanic circulation may have widespread global distribution in the Late Holocene.[17]

Animal and plant life have not evolved much during the relatively short Holocene, but there have been major shifts in the distributions of plants and animals. A number of large animals including mammoths and mastodons, saber-toothed cats like Smilodon and Homotherium, and giant sloths disappeared in the late Pleistocene and early Holocene—especially in North America, where animals that survived elsewhere (including horses and camels) became extinct. This extinction of American megafauna has been explained as caused by the arrival of the ancestors of Amerindians; though most scientists assert that climatic change also contributed. In addition, a discredited bolide impact over North America was hypothesized to have triggered the Younger Dryas.[18]

Throughout the world, ecosystems in cooler climates that were previously regional have been isolated in higher altitude ecological “islands”.

The 8.2 ka event, an abrupt cold spell recorded as a negative excursion in the δ18O record lasting 400 years, is the most prominent climatic event occurring in the Holocene epoch, and may have marked a resurgence of ice cover. It is thought that this event was caused by the final drainage of Lake Agassiz, which had been confined by the glaciers, disrupting the thermohaline circulation of the Atlantic.

The beginning of the Holocene corresponds with the beginning of the Mesolithic age in most of Europe; but in regions such as the Middle East and Anatolia with a very early neolithisation, Epipaleolithic is preferred in place of Mesolithic. Cultures in this period include:Hamburgian, Federmesser, and the Natufian culture, during which the oldest inhabited places still existing on Earth were first settled, such as Jericho in the Middle East,[20] as well as evolving archeological evidence of proto-religion at locations such as Göbekli Tepe, as long ago as the 9th millennium BC.[21]

Both are followed by the aceramic Neolithic (Pre-Pottery Neolithic A and Pre-Pottery Neolithic B) and the pottery Neolithic. The Late Holocene brought advancements such as the bow and arrow and saw new methods of warfare in North America. Spear throwers and their large points were replaced by the bow and arrow with its small narrow points beginning in Oregon and Washington. Villages built on defensive bluffs indicate increased warfare, leading to food gathering in communal groups rather than individual hunting for protection.

 

 

Projections

Published on Nov 11, 2013

Follow Michael Stevens: http://www.twitter.com/tweetsauce
EXTRA INFO & LINKS BELOW!

Dr. Julian Bayliss’ rainforest story: http://youtu.be/mni8mSS4KDU

Cool video from CGPGrey: “How Many Countries Are There?”http://youtu.be/4AivEQmfPpk

upside-down map: http://paulmencke.nl.dualdev.com/wp-c…

INTERACTIVE projection site:http://www.jasondavies.com/maps/trans…

Chromoscope: http://www.chromoscope.net/

Mercator Puzzle: https://gmaps-samples.googlecode.com/…

xkcd on maps: http://xkcd.com/977/

Earth “live”: http://aa.usno.navy.mil/imagery/earth…

interactive gnomonic: http://bl.ocks.org/mbostock/3795048

West Wing MAPS clip: http://www.youtube.com/watch?v=n8zBC2…

Earth from Mars: http://astrobob.areavoices.com/2012/0…

Earth from Saturn: http://saturn.jpl.nasa.gov/news/newsr…

“look” etymology: http://www.etymonline.com/index.php?t…

wave on a string simulation: http://phet.colorado.edu/en/simulatio…

Hi-res electromagnetic spectrum: http://www.zulyzami.com/dl16?display

Earth under different light: http://orbitingfrog.com/2008/06/25/ea…

Moon’s shadow on Earth: http://www.slate.com/blogs/bad_astron…

Bad Astronomer on twitter: https://twitter.com/BadAstronomer

Africa compared to big countries: http://cdn.twentytwowords.com/wp-cont…

Map projection info:

http://usersguidetotheuniverse.com/?p…
http://nationalatlas.gov/articles/map…
http://www.radicalcartography.net/?pr…
http://www.geo.hunter.cuny.edu/~joche…
http://education.nationalgeographic.c…
http://www.colorado.edu/geography/gcr…
http://kartoweb.itc.nl/geometrics/map…
http://www.giss.nasa.gov/tools/gproje…

What we used to think Earth looked like from space:http://blogs.smithsonianmag.com/smart…

Earth is not a perfect sphere:http://www.scientificamerican.com/art…