EDTC 6341

Team 5

 

Sharon Dressel

Jennifer Henson

Nila Pena

Ray Slapkunas

 

Opening Statement:

 

The Great Ocean Conveyor, or thermohaline circulation system (THC) describes patterns of global ocean currents. These currents link all the Earth’s oceans and play a role in stabilizing Earth’s climate as we know it. As a result, the atmosphere and hydrosphere are intricately linked. Changes to global climate, whether abrupt or gradual, may cause changes to global water currents. Changes in these currents could impact the way water is distributed through the water cycle on the lithosphere and over the hydrosphere. As a result, we could expect changes in soil salinity, changes in the rate of flow of land-based water systems, and changes in erosion patterns. All of these changes could, in turn, influence both land-based and marine organisms in the biosphere, which could then impact the atmosphere through changes in photosynthesis and respiration patterns; the hydrosphere through relocating and changing water habitats; and the lithosphere, by relocating and changing land habitats and the way organisms help shape the land and influence its chemistry. The THC is closely connected to the atmosphere, so these two systems drive some of life’s essential cycles, especially the water cycle. As a result, the THC impacts all the Earth systems, and changes to one can influence all the others. 

 

Problem Statement:

 

Studies have revealed theories that global warming could lead to an abrupt slowing of the ocean's thermohaline conveyor, which in turn could lead to harsher winter weather conditions, reduced soil moisture, and intensified winds. These events could adversely affect the world's food production and reliant population. Evidence has revealed that when the ocean thermohaline conveyor slowed in the past, climate patterns did not recover for a century or more. Have we gone far enough in studying how slow or sudden atmospheric changes could impact the THC and what the impacts to Earth's other cycles might be? In addition, what further actions can we take to stabilize global climate changes?

 

 

Recommendations/possible solutions

• Conduct further research on whether the THC is slowing down or stopping, and, if so, what factors are contributing to the decline.
• Develop a target for educating key influencers of global climate change. Ideas include:
• Work with Russian administrators to discuss the impact of dams and river outflows on the THC.
• Create a system for educating individuals in developed nations on ways they can decrease their impact on global climate change.
• Help provide statistics and research information to raise billions of dollars to help poor countries cope with global warming.  http://www.npr.org/templates/story/story.php?storyId=142882387 
• Encourage a worldwide global education program to educate individuals at all levels of the educational system on how the oceanic system operates and the importance of the role that it plays in maintaining global cycles. 
• Develop an international campaign to encourage government leaders to provide incentives to industries and car manufacturers to reduce emissions. 
• Work with city administrators in the U.S. to establish preparedness plans in the event that global climate changes and changes to the THC impact city, state, and regional services. http://www.nrdc.org/globalwarming/preparedness.pdf

 

 

Relationships:

        

Step 1: Event > Sphere Interactions

 

Event > Atmosphere

E>A,H

The scenario states that if air temperatures warm, evaporation may increase in low latitudes and cause freshwater vapor to move toward high latitudes, where it will fall into the oceans as rain or snow.

 

 

Some scientists argue that a rise in global temperatures (global warming) leads to a change in climate patterns, like El Nino and La Nina.  Increased temperatures lead to increased evaporation and to increased precipitation.  Increased rainfall/snowfall, increased flooding, grander and more catastrophic weather events in recent memory are attributed to this.

 

Event > Hydrosphere

E>H

The scenario states that changes in temperature could impact the global ocean currents, slowing or stopping the THC. 

 

As temperatures increase due to global warming, the ocean waters could have an influx of fresh water from precipitation and melting sheet ice.  The additional fresh water could reduce the ocean’s surface salinity level and thus the density level, which could slow Thermohaline Circulation.
Source: http://news.illinois.edu/news/05/1206climate.html

 

The increase of fresh water creates a lower overall density of the surface water, slowing or even stopping the sinking motion that drives thermohaline circulation.
Source: http://www.britannica.com/EBchecked/topic/235402/global-warming/274851/Ocean-circulation-changes

 

If atmospheric changes occur, the rate of evaporation could be affected.  Salt is left behind when evaporation occurs, and higher salinity allows the water to sink.  No sinking water…OCB is affected or even shut down.

 

Event > Cryosphere

E>C

(The cryosphere (from the Greek κρύος cryos "cold", "frost" or "ice") is the term which collectively describes the portions of the Earth’s surface where water is in solid form, including sea ice, lake ice, river ice, snow cover, glaciers, ice caps and ice sheets, and frozen ground (which includes permafrost). Thus there is a wide overlap with the hydrosphere. http://en.wikipedia.org/wiki/Cryosphere)

 

According to some scientists, global temperatures are increasing, and this is impacting the cryosphere.  The polar ice caps and glaciers are melting, infusing fresh water into the OCB and upsetting the necessary balance to keep the OCB in motion.

 

Event > Biosphere

E>B

As detailed in the scenario, Schwartz and Randall warn that a gradual global warming of the atmosphere could lead to a fairly sudden slowing of the ocean’s THC. The result could bring unwelcome changes to America’s croplands (and presumably crops in other parts of the world too): harsher winter weather conditions, significant reductions in soil moisture, and more intense winds in certain. The impact could be a significant reduction in the world's food production. In addition, other organisms adapted to the current weather conditions could struggle to survive.

 

I have learned in Biology classes that many marine-dwelling organisms are sensitive to salinity and temperature. If ocean temperatures or salinity change relatively suddenly, these organisms may not have time to adapt and may relocate or perish.

 

Scientists have shown that abrupt climate changes have occurred before.  During these shifts (e.g. the Younger Dryas), plant and animal life have been affected.  Future abrupt climate change could prove especially disruptive to human habitation as well as the plant life/food crops upon which humans depend for sustenance.

Current concerns are not unfounded when it comes to abrupt climate changes and global warming.  Some marine species (e.g. coral reefs) are suffering due to changes in ocean temperatures and in salinity.

 

Paleoclimatic records show that in the past the Earth has undergone rapid climate change. For example, we have clear records that show that over a decade or two, the long, snowy winters of northern New England were replaced by the milder winters of a place like Washington, D.C. Or that a sharp decrease in rainfall turned the short-grass prairie of the western Great Plains into a desert landscape like you would see in Arizona. Changes of this sort have important impacts on humans, affecting the crops we grow, the availability of water, and our energy usage. Paleoclimate records indicate that climate changes of this size and speed have occurred at many times in the past. Past human civilizations were sometimes successful in adapting to the climate changes and at other times they were not. http://www.ncdc.noaa.gov/paleo/abrupt/index.html

 

In recent years, biologists have noticed changes in ecosystems that reflect changes in climate. The extinction of the golden toad coincided with reductions in moisture air, in the cloud forests of Costa Rica. 20 out of 50 species of toads have disappeared and other animals, like the toucans and other bird species have moved to higher altitudes because of the warmer and drier air. 35 species of butterflies have changed their migratory patterns. Polar bears have less weight, believed to be the result of earlier snow melts. Songbird numbers and patterns have changed in four states of the US Midwest.  There is less phytoplankton in the Ross Sea, which affects the Antarctic food chain, which is where many whales feed at some part of their yearly journeys. http://www.exploratorium.edu/climate/biosphere/data5.html

Event > Lithosphere

E>L

The flow of ocean currents carries sediments and various materials key in the formation and shaping of landforms.  If the OCB is stopped due to climate change, the deposition of those sediments and, ultimately the formation of land, could be impacted.

 

I wonder if changes in global ocean currents would change current water erosion patterns, altering the shape of the lithosphere. I also wonder if increases in evaporation in some areas would change soil salinity in other areas.

 

 

Step 2: Sphere > Event Interactions

 

Atmosphere and Event 

A>E

 The scenario states that warming air temperatures could cause large amounts of currently frozen water to melt in polar regions. In addition, it could cause evaporation to increase in low latitudes and freshwater vapor to move toward high latitudes, where it will fall into the oceans as rain or snow.

 

Hydrosphere and Event 

H>E
The scenario states that an increase in freshwater river runoff to the Arctic Ocean from Russia could disrupt the Arctic THC. I surmise that it would reduce ocean salinity levels, and that it may also change ocean temperatures if the runoff is warmer or colder than the ocean water.

 

Biosphere and Event 

B>E
The scenario suggests that the actions of humans that are contributing to an increase in global warming and that are changing freshwater runoff patterns could be aggravating or accelerating the THC changes.

 

Scientists discovered many ways that humans and other organisms exert powerful influences to climate change. Forests in particular are deeply involved in the carbon cycle, scientists argue over just what deforestation means for climate. By the 1980s, it was certain that all the planet's ecosystems were major players in the climate changes that would determine their own future. http://www.aip.org/history/climate/biota.htm

 

Lithosphere and Event 

L>E 

I surmise that changes in the atmosphere over land could change river discharge locations and rates. It might increase erosion and sediment deposition in some areas and reduce it in others. I wonder if these changes might impact the THC. 

 

 

Step 3: Sphere > Sphere Interactions

 

Atmosphere  

A>H 

It seems to me that the atmosphere and hydrosphere are so closely connected in this scenario that it is difficult to separate one from the other. The scenario states that even gradual changes in the atmosphere could impact the THC. 

 

If there is a change in temperatures in the atmosphere, wind speeds are affected, and so are ocean currents.

 

A>B 

Based on my prior understanding of ecology, I know that organisms not well adapted to changes in global weather patterns could relocate or perish. Those that relocate could disrupt habitats and cause ecological imbalances. Some species may become extinct if, as Schwartz and Randall warn, these changes occur swiftly because they will not have time to adapt. Because species are interdependent, I surmise that we could experience another mass extinction. 

 

A>L 

I can infer from the scenario that changes in weather patterns would impact the upper regions of the lithosphere. Reduced moisture in valuable top soil is predicted, and we can assume that dramatic changes in winds and rainfall would cause new trends in weathering and erosion.

 

I wonder if these changes might also lead to an increase in severe thunderstorms, hurricanes, and/or tornadoes.

 

Hydrosphere 

H>A 

Based on my prior understanding of ecology, I know that organisms not well adapted to changes in global ocean patterns could relocate or perish. Those that relocate could disrupt habitats and cause ecological imbalances. Some species may become extinct if, as Schwartz and Randall warn, these changes occur swiftly because they will not have time to adapt. Because species are interdependent, I surmise that we could experience another mass extinction.

 

Changing ocean temperatures impact weather formation (e.g. if cooled, hurricanes are less likely to form there) 

 

H>B 

I can infer that with significant changes to ocean water in water sources in a short period of time, the habitat of organisms could change faster than the organisms living in the hydrosphere could adapt. Some may relocate. Others may perish.  

 

Some ocean life cannot function outside of its narrow thermal niche.  The bleaching of coral reefs is proof positive that warming ocean temperatures can have a direct and detrimental effect on ocean creatures and vegetation.

 

H>H

Increased dumping of fresh water into the Arctic Ocean is changing the balance and salinity of the ocean.  The OCB is affected and can even be stopped as a result.

 

H>L 

I surmise that changing global ocean currents could lead to changing patterns in the erosion of coastlines. An increased volume and rate of flow in some areas and decreased volumes and rates of flow in others could influence the development of new formations along the coasts and larger river deposits upstream. 

 

Biosphere 

B>A 

If changes to the THC lead to a reduction in oxygen-producing plants on land or in water, I can infer that the amount of oxygen produced will be reduced, at least in some areas. This would alter the chemistry of the atmosphere and further influence changing weather patterns. 

  

B>H 

I can infer that a reduction of more vulnerable organisms in the hydrosphere would lead to a reduction in the organisms that depend upon them. It will also influence the chemistry of the water as the water will contain more decaying matter and less living matter. 

 

B>L 

I can infer that significant changes in the hydrosphere and atmosphere would change animal habitats, causing some organisms that could not live in some areas to relocate or die out. Because some organisms directly influence the lithosphere as well as the life growing on it, the lithosphere could also change; e.g. changes in the chemistry and fertility of soil and shape of the land previously altered by organisms or newly altered by relocated organisms. 

 

Lithosphere 

L>A 

Based on the scenario, the lithosphere could get wetter in some areas. This would lead to an increase in evaporation in these areas.

 

L>H 

I can infer that with the widespread changes in atmosphere and hydrosphere, patterns of erosion could change introducing increased sediment and perhaps even uprooted vegetation and structures into rivers, lakes, streams, and creeks; these water sources would then become clogged, changing their rate of flow and taking on a new shape and appearance. 

 

L>B 

I can infer that as sediment is relocated and redistributed, so too will the organisms dependent upon it. Some organisms will die out in previously rich areas and others may flourish where they previously could not.

 

 

Evidence

The Associated Press. (Producer) (2011). Financing battle emerges at climate change talks [Radio series episode]. In Morning Edition. NPR. Retrieved from http://www.npr.org/templates/story/story.php?storyId=142882387

 

Natural Resources Defence Council. (2008, April). Preparing for global warming: A framework for protecting community health and the environment in a warmer world. Retrieved from http://www.nrdc.org/globalwarming/preparedness.pdf