Do Endogenic Processes Influence Global Climate Systems Environmental Sciences Essay

All processes that take place inside Earth (and other planets) are considered endogenous. They make the continents migrate, push the mountains up, and trigger earthquakes and volcanism. Endogenous processes are driven by the warmth that is produced in the core of Earth by radioactivity and gravity.

The geography and movement of tectonic plates is a key influence on global climate as it determines the form of the ocean basins, Patterns of heat ransfer in the oceans, large scale atmospheric circulation and the geometry of mountain chains. The movement and geometry of the lithospheric plates is a key long term influence on global climate and hea transfer and plae movements can be both vertical e.g the formation of the Himalayas and the Tibetan plateau or horizontal e.g sea floor spreading or the closing of the panama seaway and the development of the north atlantic gulf stream.

Internal energy drives endogenic processes such as plate tectonics, volcanic activity, seismicity.

The geography of the tectonic plates is a key influence on a global climate, this influences: the form and size of the ocean basins and land masses, patterns of heat transfer in the oceans – thermohaline circulation, large scale atmospheric circulation and vertical heat exchange, the location and elevation of mountain chains and plateaus, the amount of elevated crust.

The formation of the Himalayas and the Tibetan plateau that began 52 to 44ma key events that led to a step change in the climate system and long term global cooling.

Horizontal crustal movement – the closing of the panama seaway around 4 ma and the development of the north atlantic gulf stream taking warm water to higher latitudes – a key factor in the formation of ice sheets in the northern hemisphere.

The closing of the panama seaway around 4ma and the development of the north atlantic gulf stream taking warm water to higher latitudes.

The movement and geometry of the lithospheric plates is a key longterm influence on global climate and heat transfer, vertical crustal movements are most rapid at plate boundaries and we will be exploring their potential impact on weathering rates and carbon cycle.

Location and elevation of mountain chains and high plateau landscapes across the earths surface is a key influence on climate over a range of timescales.

The essay is about the last 65 million years, so the Big Bang theory

is not really relevant. You need a nice range of examples to show how

endogenic processes can influence global climate (long and short

term). We covered some in the lectures (i.e. vertical and horizonatal

crustal movements). We did not really look at volcanic processes, but you need to mention them too (short and longterm impacts) we mentioned other controls too (not related to endogenic processes) so you can mention them briefly to round things off.

When Mount Pinatubo erupted in the Philippines June 15, 1991, an estimated 20 million tons of sulfur dioxide and ash particles blasted more than 12 miles (20 km) high into the atmosphere. The eruption caused widespread destruction and loss of human life. Gases and solids injected into the stratosphere circled the globe for three weeks. Volcanic eruptions of this magnitude can impact global climate, reducing the amount of solar radiation reaching the Earth’s surface, lowering temperatures in the troposphere, and changing atmospheric circulation patterns. The extent to which this occurs is an ongoing debate. Large-scale volcanic activity may last only a few days, but the massive outpouring of gases and ash can influence climate patterns for years. Sulfuric gases convert to sulfate aerosols, sub-micron droplets containing about 75 percent sulfuric acid. Following eruptions, these aerosol particles can linger as long as three to four years in the stratosphere.

Major eruptions alter the Earth’s radiative balance because volcanic aerosol clouds absorb terrestrial radiation, and scatter a significant amount of the incoming solar radiation, an effect known as “radiative forcing” that can last from two to three years following a volcanic eruption.

“Volcanic eruptions cause short-term climate changes and contribute to natural climate variability,” says Georgiy Stenchikov, a research professor with the Department of Environmental Sciences at Rutgers University. “Exploring effects of volcanic eruption allows us to better understand important physical mechanisms in the climate system that are initiated by volcanic forcing.”

Stenchikov and Professor Alan Robock of Rutgers University with Hans Graf and Ingo Kirchner of the Max Planck Institute for Meteorology performed a series of climate simulations that combined volcanic aerosol observations from the Stratospheric Aerosol and Gas Experiment II (SAGE II) available from the Langley DAAC, with Upper Atmosphere Research Satellite (UARS) data from the Goddard Space Flight Center DAAC. The research team ran a general circulation model developed at the Max Planck Institute with and without Pinatubo aerosols for the two years following the Pinatubo eruption. To study the sensitivity of climate response to sea surface temperature, using data from the NASA Jet Propulsion Laboratory DAAC, they conducted calculations with climatologically mean sea surface temperature, as well as with those observed during particular El Niño and La Niña periods.

By comparing the climate simulations from the Pinatubo eruption, with and without aerosols, the researchers found that the climate model calculated a general cooling of the global troposphere, but yielded a clear winter warming pattern of surface air temperature over Northern Hemisphere continents. The temperature of the tropical lower stratosphere increased by 4 Kelvin (4°C) because of aerosol absorption of terrestrial longwave and solar near-infrared radiation. The model demonstrated that the direct radiative effect of volcanic aerosols causes general stratospheric heating and tropospheric cooling, with a tropospheric warming pattern in the winter.

“The modeled temperature change is consistent with the temperature anomalies observed after the eruption,” Stenchikov says. “The pattern of winter warming following the volcanic eruption is practically identical to a pattern of winter surface temperature change caused by global warming. It shows that volcanic aerosols force fundamental climate mechanisms that play an important role in the global change process.” This temperature pattern is consistent with the existence of a strong phase of the Arctic Oscillation, a natural pattern of circulation in which atmospheric pressure at polar and middle latitudes fluctuates, bringing higher-than-normal pressure over the polar region and lower-than-normal pressure at about 45 degrees north latitude. It is forced by the aerosol radiative effect, and circulation in winter is stronger than the aerosol radiative cooling that dominates in summer.

Man-made, or “anthropogenic” emissions can make the consequences of volcanic eruptions on the global climate system more severe, Stenchikov says. For instance, chlorofluorocarbons (CFCs) in the atmosphere start a chain of chemical reactions on aerosol surfaces that destroy ozone molecules in the mid-latitude stratosphere, intensifying observed stratospheric ozone depletion.

“While we have no observations, the 1963 Agung eruption on the island of Bali probably did not deplete ozone as there was little atmospheric chlorine in the stratosphere. In 1991 after the Pinatubo eruption, when the amount of CFCs in the stratosphere increased, the ozone content in the mid-latitudes decreased by 5 percent to 8 percent, affecting highly populated regions,” says Stenchikov.

NASA and the National Science Foundation have funded Robock and Stenchikov to study the Pinatubo eruption in more detail, and to conduct another model comparison with the volcanic aerosol data set. They plan to combine SAGE II data with available lidar and satellite data from various DAACs to improve their existing data set.

By understanding the impact of large volcanic eruptions on Earth’s climate system in more detail, perhaps scientists will be in a better position to suggest measures to lessen their effects on people and natural resources.

Both technological change and economic growth are seen as major determinants of future global energy demand levels, the associated carbon dioxide (CO2) emissions, and global climate impacts Until recently, however, the modelling of energy-economy-climate interactions has largely regarded technological progress as an exogenous process, rather than as endogenous technological change.

Energy Economics

Volume 24, Issue 1, January 2002, Pages 1-19

a momentary glance at a map of the world today to realise that the disposition of the continents has a marked effect on both local and global climate. Not the least of these effects results from the difference in the thermal properties of land versus ocean – a continental region will be colder in winter and warmer in summer than an oceanic region at any given latitude. Moreover mountain belts formed as a consequence of plate tectonic activity dramatically modify rainfall through the effects of orography – the development of a rain shadow on the leeward side of mountain belts.

Global climate is also strongly controlled by ocean currents. For example, northwestern Europe is significantly warmer than other regions at similar latitudes because of the warming effects of the Gulf Stream and North Atlantic Drift. The reversal of oceanic currents in the equatorial Pacific – a phenomenon known as El Niño – has a far-reaching effect on climate around the Pacific. Ocean currents depend on the geometry of the oceans and this is controlled by plate tectonics. Hence, over geological timescales the movement of plates and continents has a profound effect on the distribution of land masses, mountain ranges and the connectivity of the oceans. As a consequence, plate tectonics has a very direct and fundamental influence on global climate.

http://openlearn.open.ac.uk/mod/resource/view.php?id=172207

The climate of modern Antarctica is extreme. Located over the South Pole and in total darkness for six months of the year, the continent is covered by glacial ice to depths in excess of 3 km in places. Yet this has not always been the case. 50 Ma ago, even though Antarctica was in more or less the same position over the pole, the climate was much more temperate – there were no glaciers and the continent was covered with lush vegetation and forests. So how did this extreme change come about?

The modern climate of Antarctica depends upon its complete isolation from the rest of the planet as a consequence of the Antarctic Circumpolar Current that completely encircles Antarctica and gives rise to the stormy region of the Southern Ocean known as the roaring forties. The onset of this current is related to the opening of seaways between obstructing continents. Antarctica and South America were once joined together as part of Gondwana and were the last parts of this original supercontinent to separate. By reconstructing continental positions from magnetic and other features of the sea floor in this region, geologists have shown that the Drake Passage opened in three phases between 50 Ma and 20 Ma, as illustrated in Figure 32. At 50 Ma there was possibly a shallow seaway between Antarctica and South America, but both continents were moving together. At 34 Ma the seaway was still narrow, but differential movement between the Antarctic and South American Plates created a deeper channel between the two continents that began to allow deep ocean water to circulate around the continent. Finally, at 20 Ma there was a major shift in local plate boundaries that allowed the rapid development of a deep-water channel between the two continental masses.

The coincidence of the change in motion of the Pacific Plate with changes in plate motions between S. America and Antarctica shows how the motions of all the plates are interconnected – a change in the true motion of one plate leads to changes in the true motions of many others.

While these plate motions were taking place the effect on Antarctica was profound. By 34 Ma the climate cooled from the temperate conditions that previously existed. This was sufficient for glaciers to begin their advance, and was followed by a period of continued cooling until at about 20 Ma, glaciation was complete. Even though the Drake Passage first opened at 50 Ma it was not until it opened to deep water at 34 Ma that glaciation really took hold

Today, the Antarctic Circumpolar Current is the strongest deep ocean current and its strength is responsible for the ‘icehouse’ climate that grips the planet. The opening of the Drake Passage had both a local and a global effect, initially cooling the climate of Antarctica from temperate to cold and ultimately playing an important role in the change from global ‘greenhouse’ conditions 50 Ma ago to the global ‘icehouse’ of today.

This example shows how plate tectonics, continental drift and the opening and closing of seaways can have a profound influence on both local and global climate. Throughout the Phanerozoic there were long periods when the Earth was much warmer than today – often called a ‘greenhouse’ climate – and other times when it was cold – called an ‘icehouse’ climate. These cycles, like the Wilson cycle, occur over periods of 100 Ma, reflecting the timescale of plate movements and the growth and destruction of oceans. Given the clear link between ocean circulation and climate, and the similar timescales of global climate change and plate motions, it is inescapable that one of the chief controls on long-term changes in the global climate must be plate tectonics.

Every two to seven years a climatic disturbance brings floods to California, droughts to Australia, and famine to Africa . Known as El Nino, it is essentially a warming of surface waters in the eastern Pacific near the equator. Although scientists understand the mechanics of El Nino, its origins have yet to be determined. Most believe that the interaction between the atmosphere and the sea somehow generates this climatic disturbance that wreaks havoc upon those regions of the world that lie in its path.

But now a new theory on the origins of El Nino has been proposed and, surprisingly, it has very little to do with the atmosphere or the sea. The new theory suggests that the primary mover behind El Nino is hot magma welling up between tectonic plates on the Pacific sea-floor. The upwelling magma heats the overlying waters enough to affect the ocean surface, initiating the cascade of events that brings on the wrath of El Nino.

Volcanic Ash

Eruptions, like that pictured above, throw tons of ash into the atmosphere, and have short term affects of the climate. If the eruption is potent enough, the ash will stop some of the shortwave radiation coming in from the Sun. This, in turn, will lead to a decrease in the global temperature. The reason for this is that the shortwave radiation that comes in from the Sun and reaches the Earth’s surface, gets absorbed in the the Earth. About 4 to 6 hours later, the Earth reradiates that energy in the form of longwave radiation. This is where the temperature comes from. So if some of the sunlight is shut off, then this will lead to a decrease the global temperature. With the eruption of Mount Pinatubo in June 1991 (image above), about 22 million tons of ash was thrown into the atmosphere. This was enough to block a fraction of the sunlight from reaching the Earth’s surface, which cooled the global temperature on Earth by as much as 0.5 degrees C. The most powerful eruption in recorded history, the eruption of the Tambora Volcano in Indonesia in April of 1815, threw up so much ash that the global temperature on Earth fell by as much as 3 degrees C. Europe and North America know this time as “the year without a summer.” The volcanic ash does not keep the temperatures down for a very long period of time geologically speaking, so its impacts are on a short term basis.

Rain-Shadow Effect

The long term impacts of volcanoes come from a look at simple geography. Volcanoes are gigantic mountains, so their affect on climate is the same as a normal mountain. This leads to the rain-shadow effect (explained in the Continental Movement section), which comes into play with volcanoes just as it does with mountain building. Until that volcano can be eroded away, it will continue to have some sort of impact on climate. This can last for thousands of years.

Volcanoes have quite a bit of affect on climate. And this affect can be rather short term (volcanic ash) or long term (rain-shadow effect) in nature. Again biology can be affected by this too. For example, a desert area may quickly develop on the leeward side of a new volcano. If life is not able to adjust, extinction will become a significant threat.

http://www.djburnette.com/projects/volcanoes.html