Lecture 5

what is environmental agency?

• A person’s/ groups ability to impact the environment

What did the greeks begin to question?

• models of the env and role of humans intentionally

• traditional views of nature continue to this day

What did Aristotle insights lead us to?

• towards process han pure ideals of nature how nature should work

What did Francis bacon descirbe?

• why its hard to remove bias

• Idols of the Mind: tribe, market, cave theatre

What is knowledge according to Bacon?

• In book New Atlantis

• Knowledge is power in the context of human aspirations

  • Science gives knowledge

  • knowledge gives control

What does voltaire push readers to do?

• instead of being trapped in a moment of time

• look beyond it

• overcome idols

What makes a perfect scientists according to voltaire?

• No to teology , politics, etc

• Expanded sense of scale

• Great inclusion (ecosystem heuristic)

• Modularity 

• incremental steps (ecosystem heuristic)

• look for emergent patterns

What is the ecosystem heuristic

• heuristic: proceeding to a solution by trial and error or by rules that are only loosely defined

• rule of thumb, used to quickly understand and make decisions within the complex and dynamic interactions between human societies and natural environments

What is modularity?

• people working on different parts (ex: science, policy, humanities) in a issue

  • Pick a part and put together parts after

What book did Tansley write?

The Use and Abuse of Vegetational Concepts and Terms

What was Tansley’s beliefs?

• Rejected notion of a complex, highly integrated community organized along organismic lines

What is the ideal a scientist should strive for?

• elimination of uneccesarry metaphors to explain nature

• scientists need systematics tools or processes to incrementally examine complex systems

Who was R. Lindeman?

• 1915-1942

• effectively employed the term ecosystem

  • in paper “The trophic-Dynamic aspect of Ecology”

Who was Charles Elton in relation to Lindeman?

• pioneered trophic-dynamic approach (1927) in Animal ecology

• discussed food chains and links between producers, consumers, reducers and decomposers

What did Lindeman see in relatinon to Elton?

• separation of the biotic community and the abiotic community as artificial

• Non-living nascent ooze rapidly reincorporated through "dissolved nutrients" back into the living "biotic community".

What was R. Lindeman’s main point?

• ecosystem defined as s the system composed of physical-chemical-biological processes active within a space-time unit of any magnitude, i.e. the biotic community plus its abiotic environment

What did the inclusion of abiotic in ecosystems cause?

• opened up their complexity to analysis

• Expanding scale —> expanded potential number of factors and interactions that could be taken into account

Why are experimental lakes important?

• Many valuable inferences have been drawn from observational data on both natural and polluted lakes without recourse to premeditated experiment.

  • most of our existing knowledge of lakes has been derived from the observation of natural events

What is the issue with observation alone?

• observation alone is rarely sufficient for the construction of an exact science,

  • particularly when many variables play interconnected roles in the determination of final states.

  • True appreciation of causes and mechanisms demands freely ranging hypotheses and experimental tests.

Who was Jens Esmakr?

• geologist (1824)

• argued for a sequence of worldwide ice ages —> climate could drasticaly change

• intriguing quandary for science was therefore, identifying the cause

Who was Tyndall?

• 1859

• how the atmosphere might influence atmospheric temperatures

• Opinion held that gases were transparent to radiation —> checked in lab

  • CO2 was almost opaque to heat radiation

  • Small amounts in the atmosphere would absorb radiation —> This would be transferred as heat to air in middle latitudes

    • good part of the radiation that rises from the surface is absorbed by CO2 in the middle levels of the atmosphere

Who was Arrhenius?

• 1896

• attempted to calculate the effects of atmospheric CO2 on temperature

• Greenhouse effect just speculation at that time

• created the energy budget: added up how much solar energy was received, absorbed, and reflect 

• looked at feedback systems: mutual reaction of the physical conditions"

What did Arrhenius suggest about the Artic region?

• early 1900s

• drop in temperature in Arctic region 

  • Bare ground in the summer would become covered with snow all year-round.

  • The higher "albedo" or reflectivity resultant from snow cover would lower the temperature still more,

• Positive feedback: self-reinforcing process

  • small changes in inital dirver —> dramatic effects

  • suggested that such a cycle could turn a minor cooling event into an ice age.

What other simple feedback did Arrhenius use?

• • Warmer air would hold more moisture.

• Since water vapour is itself a greenhouse gas, the increase of water vapour would augment the temperature rise

• This would intensify the influence of any such change.

What were the main calculations for Arrhenius?

• effect of a decrease in CO2

• what doubling of CO2 would do: 5-6 C increase

• Result: CO2 atmospheric levels could change over time

Who was Arvid Hogbom (less imp)

• extended Arrhenius work

• compiled estimates of how CO2 cycles through natural geochemical processes (i.e. through volcanoes, or by the uptake by oceans) AND the emissions from factories

Who was Croll?

• 1880s

• Research on ice ages incorporated planetary cycles

• proposed cold winters counted for keeping reflective snow in place —>wrong

Who was Milankovitch?

• extended crolsl worok

• developed astronomical calculations regarding solar cycles and plugging them into equations that simulated the global climate.

  • paid closer attention to how much sunlight was received

• Cold summers counted keeping reflective snow in space

Who were Alfred Wegener and Wladimir Koppen?

• meterologists

• continents drifted from tropics to Arctic and back

  • traces of ancient ice caps found in rock beds near the equator, and fossils of tropical plants in rocks near the poles (evidence of dramatic past climates shifts)

what did Alfred Wegener and Wladimir Koppen say about ice sheets?

•  large ice sheets that reflected sunlight, could only persist if they rested on land, not ocean … thus →

• Ice ages began when Greenland wandered north and, the solar radiation was enfeebled.

Arrenhius + Croll + Milankovitch + Wegern and Koppen summary

• Arrenhius: albedo was the key factor determining whether snow melted or persiste

• Croll (1880s) and Milankovitch (1920s): variations in the amount of sunlight that reached the Earth gave rise to ice ages when enfeebled sunlight allowed excess snow accumulation

• Wegern and Koppen (1920s): e large ice sheets that reflected sunlight, could only persist if they rested on land, not ocean … thus → Ice ages began when Greenland wandered north and, the solar radiation was enfeebled.

What were realizations in the 1930s?

• beginning to see the inter-relatedness of various process and mechanisms

• positive feedback magnify small changes

• 1932: Humphreys —> teetering on ice age some relatively mild geologic action would be sufficient to start going

What were realizations in the 1950s?

• try to find total carbon contained in an ocean layer, in the air, in vegetation, and so forth

• bookkeeping studies s which added up the entire atmosphere's stock of heat, energy, and chemicals.

• Goal: balance each budget in an assumed equilibrium.

What happened in the 1960s?

• climatologist Mikhail Budyko: simplified mathematical model

  • Zero-dimensional" model looked at heat balance of Earth

• Global temperatures shoot up as glaciers ice melted —> uniformly warm planet

• Earth cooled —> more water forze —> a stable state of total glaciation —? a frozen ball of ice

What happened during the Mega El Niño?

• Increased pressure of CO2 (410-860 ppm) —> El ninos intensified

  • deforestation + reef demise + plankton crisis —> cascading environmental disaster

  • Reduced carbon sequestration initiated positive feedback —> warmer hothouse —> stronger El Niños —> higher climate variability + warming —> led to catastrophic but diachronous terrestrial and marine losses.

What was the Pre-WWII cultural understanding of env?

• result: ice age

• disconnected relations

• military purposes low

What was the Post WWII cultural pragmatism (valuates ideas, beliefs, and actions based on their practical consequences and usefulness in solving problems) understanding of env?

• better understanding of weather forecast and control

• higher military purpose, economics, and politics

• still mostly disconnected

What was the Environmental transition understanding of env?

• focus on global warming

  • all focused on it

• Military purpose still high, culture low

What was the modern environmental understanding of env?

• environmental ethos high

• all focused on global warming

• military security smaller

What was the WV (??) Environmental transition understanding of env?

• 1.5 - 2 C global mean temperature

• politics, economics, environ ethos, and miliatry security as equally important

What does a theory of climate change require?

• greatly expanded conception of space and time

• 1) that our atmospheric system has changed over extended scales; and oddly …

• 2) that we can imagine and now measure … other climatic systems.

What is the diurnal cycle?

a daily, 24-hour pattern of processes and events caused by Earth's rotation. It encompasses the rise and fall of daily temperatures, fluctuations in weather patterns like storms, and the rhythms of biological activity in living organisms.

how are exoplanets used to understand Earth’s environment?

• analogous response of temperate terrestrial exoplanets and Earth’s climate dynamics to greenhouse gas supplement

• James Webb Space Telescope: characterizing the atmospheres

  • motivate us to understand

  • exoplanetary atmospheres to constrain habitability.

What is TRAPPIST-1e and what do we use it for?

• earth-like exoplanet

• study the influence greenhouse gas supplement has on the atmosphere of TRAPPIST-1e, an Earth-like exoplanet, and Earth itself by analyzing ExoCAM and CMIP6 model simulations.

• analgous relationship btwn CO2 supplment and amplified warming at non-irradiated regions (night side and polar) —> such spatial heterogeneity results in significant global circulation changes

what is part of scale for evolution

ETE: expected time to extinction