Physics in Climate Change - exam 3

steps of thermohaline circulation

a. surface currents are driven by wind

b. evaporation and sea ice formation increases the salinity of seawater

c. high-salinity water is denser and sinks to the bottom of the ocean

d. sinking water drives deep water horizontally along the ocean bottom

e. deep water circulates finding warm zones that it can rise to the surface

Ocean acidication

the process by which dissolved CO2 alters the ocean chemistry to decrease the pH of the ocean

pH

a measure of Hydrogen ion concentration

ocean pH

projected to be about 7.7 by 2100

ocean pH decrease

0.1 since 1770

Shell forming sea creatures risk from ocean acidification

due to the consumption of carbonate ions impedes calcification

Dissolved CO2 forms

carbonic acid (H2CO3)

two factors contributing to sea level rise

thermal expansion and meltwater

Since 1993, global sea levels rise

about 10 cm

what GRACE-FO tracks

global water movements and changes to glaciers and ice sheets by measuring gravitational anomalies

GRACE-FO

a pair of satellites that beam microwaves back and forth. As the gravitational force exerted on them changes due to variations in mass density, the distance between the changes slightly. This change is used to infer the concentration of mass on the Earth

The parts of the cryosphere

Snow

Ice

Permafrost

Glaciers

Ice Shelves/icebergs

Sea ice

Cryosphere amplifies climate changes through

snow, ice, and permafrost feedbacks

snow precipitation that forms when…

water vapor freezes. It's not frozen rain, but a crystallization of ice that typically forms in clouds

snow's effect on climate

bright white color reflects sunlight, cooling the planet, and affecting climate

snow provides...

an insulating layer during winter, under which plants and animals can survive the coldest months

without snow cover...

the ground absorbs about four to six times more of the sun's energy

the presence/absence of snow controls...

patterns of heating and cooling over Earth's land surface more than any other single land surface feature

the largest single component of the cryosphere

snow cover

On a large scale, snow cover helps

regulate the exchange of heat between Earth's surface and the atmosphere

On a smaller scale, variations in snow cover can affect

regional weather patterns

Snow's albedo

how much sunlight it reflects back into the atmosphere. it is very high, reflecting 80 to 90 percent of the incoming sunlight

Glacial ice

where snow has accumulated for hundreds, even thousands of years, it compresses into this. Scientists drill into this and recover cores to get information about Earth's past climate

Ice

less dense than liquid water, allowing it to float in oceans, lakes, and rivers

Permafrost

any type of ground-from soil to sediment to rock-that has been frozen continuously for a minimum of two years are as many as hundreds of thousands of years

permafrost can extend down beneath the earth's surface from…

a few feet to more than a mile

Moulin

a nearly vertical channel in ice that is formed by flowing water

ice shelves

floating tongues of ice that extend from glaciers grounded on land

ice shelves importance

without a shelf to slow its speed, the glacier that feeds the ice sheet accelerates

Ice sheets shrink by...

Calving & disintegration

Calving

when large chunks of ice break off the face of a glacier

disintegration

occurs when the internal stresses become too large and an ice sheet can no longer support its weight and it collapses into the ocean

icebergs are generally formed through…

calving

percentage an iceberg is seen above the water

10%

Archimedes' Principle

states that an object in a fluid displaces a volume of fluid equal to the volume of the object

bouyant force

equal to the weight of the displaced fluid

when the object will float

when the buoyant force exceeds the weight of the object

Sea ice

frozen seawater that floats on the ocean surface. It forms, grows, and melts entirely in the ocean

sea ice melting (can/cannot) lead to an increase in global sea level

cannot

sea ice formation leads to a...

local increase in salinity and helps drive the thermohaline circulation

Sea ice is important because...

it can influence ocean currents and because it increases the albedo of the Earth

ice-albedo feedback occurs...

when the ice melts and lowers the albedo resulting in greater absorption of incoming radiation. This increased absorption leads to additional warming and more melting which lowers the albedo even further exacerbating the problem

models are...

approximations; by their very nature they simplify the problem by leaving something out

just because models are approximations does not mean that...

they do not capture important features of a physical phenomenon

early climate models looked solely at...

atmosphere-land interactions

current climate models incorporate...

a wide variety of phenomena including aerosols, vegetation, and atmospheric chemistry, in addition to the atmosphere, land, and ocean components

increased computational power

allowed the spatial resolution of climate models to improve significantly, from 500 km in the first assessment report to 110 km in the fourth assessment report

two simple models we examined

the zero-dimension energy balance and the N-layer model

energy balance models do no attempt to resolve...

the dynamics of the climate system (e.g. wind, ocean, currents, convections, etc)

the different types of climate models

a) energy balance models

b) box models

c) radiative-convection models

d) statistical-dynamical models

e) general circulation models

box models

split the modeled environment into box and look at energy exchange between adjacent boxes

radiation

energy that comes from a source and travels through space at the speed of light

convection

the transfer of energy through the bulk movement of a fluid

radiative-convection models

care extensions of the N-layer model with convective transfer between layers

Statistical-Dynamical models

combine horizontal energy transfer with radiative-convective transfer

Statistical-Dynamical models are useful for

studying horizontal energy flows and the processes that disrupt them.

General Circulation Models (GCMs)

numerical models that represent the physical processes in the atmosphere, ocean, cryosphere, and land surface. They are the most advanced tools currently available for simulating the response of the global climate system to increasing greenhouse gas concentrations

GCMs are a full three-dimensional model of the planet that incorporate important physical principles including:

(a) Conservation of Energy

(b) Conservation of Momentum

(c) Conservation of Mass

(d) Ideal Gas Law

ideal gas law

expresses the relationship between pressure, volume, absolute temperature, and number of molecules of a gas

Representative Concentration Pathways (RCPs)

quantify future greenhouse gas concentrations and the radiative forcing (additional energy taken up by the Earth system), due to increases in climate change pollution

RCP8.5

considered business as usual

Shared Socioeconomic Pathways (SSPs)

scenarios of projected socioeconomic global changes up to 2100

SSPs are used to...

derive greenhouse gas emissions scenarios with different climate policies

validation

the process for verifying the accuracy of climate models

forecasting

the process of making predictions based on past and present data

hindcasting

a process of testing computer models (e.g. climate change models) by having them compared to the actual historical observations to determine how well the models matched the historical record

emergent patterns in climate models refer to...

the realization of physical phenomena such as hurricanes through the application of fundamental physics, i.e., the phenomena are not programmed in the model but arise (emerge) due to the state of computed environment

geoengineering

refers to a set of emerging technologies that could manipulate the environment and partially offset some of the impacts of climate change

solar radiation management

one geoengineering strategy that seeks to control the amount of radiation impinging on the Earth with the goal of reducing warming

stratospheric aerosols injection

mimics the effects of volcanoes by injecting sulfate particles into the stratosphere to increase the albedo of the earth

injection of sulfur into the stratosphere would increase the amount of...

acid rain

aerosols injected into the stratosphere would have a lifetime of about...

two years and would need to be continually replenished

marine cloud brightening

increases the albedo by shooting salt-rich water particles into the sky, long-lasting clouds could get formed because the particles would be smaller than normal water droplets, and would have a greater surface area

a space sunshade or sunshield

a parasol that diverts or otherwise reduces some of a star's radiation, preventing them from hitting a spacecraft or planet and thereby reducing its insolation, which results in reduced heating

if we wanted to completely counteract the cumulative effects of human-caused global warming to date, we'd only need to block out approximately \___% of the Sun's light that would normally arrive at Earth on a continuous basis

2

solar radiation management

strategies only tackle the warming aspects of climate change and do nothing to reduce atmospheric CO2 concentrations and other factors like ocean acidification

iron fertilization

he intentional introduction of iron to iron-poor areas of the ocean surface to stimulate phytoplankton production. This is intended to enhance biological productivity and/or accelerate carbon dioxide (CO2) sequestration from the atmosphere

precautionary principle

a broad epistemological, philosophical, and legal approach to innovations with the potential to cause harm when extensive scientific knowledge on the matter is lacking

Carbon capture and storage (CCS)

refers to a collection of technologies that can combat climate change by reducing carbon dioxide (CO2) emissions

insolation

solar radiation received in the Earth's atmosphere or at its surface

semiconductor

materials which have a conductivity between conductors (generally metals) and nonconductors or insulators (such as most ceramics)

n-type (negative type) semiconductor

a type of semiconductor that is made by adding an impurity with an extra electron to a pure semiconductor

p-type (positive type) semiconductor

A type of semiconductor that is made by adding a trivalent impurity to a pure semiconductor

electromagnetic induction

the phenomenon of producing an electromotive force in a circuit by changing the magnetic flux through a coil

electromotive force (emf)

a voltage that is produced that will drive electrons around a circuit. it is fundamentally not a force

magnetic flux

a measure of the amount of magnetic field that crosses some area such as the plane of a coil

tidal energy

a form of power produced by the natural rise and fall of tides caused by the gravitational interaction between Earth, the sun, and the moon. Tidal currents with sufficient energy for harvesting occur when water passes through a constriction, causing the water to move faster

ocean tides

cyclic variations of sea levels on coastlines as a result of the gravitational forces from the moon and the sun, and the centrifugal forces due to the rotation of the Earth

The period between the high sea level, called flood, and the low sea level, called ebb, is about...

12.5 hours, or half a lunar day

tidal streams

formed by the horizontal fast-flowing volumes of water caused by the ebb and flow of the tide. Hence tidal stream generators make use of the kinetic energy of moving water to power turbines

tidal stream generators work the exact same way...

wind turbines use the wind to power turbines

tidal barrage

a dam-like structure used to capture the tidal energy from masses of water moving in and out of the seashore

tidal barrages generate electricity using...

the difference in the vertical height between the incoming high tides and the outgoing low tides

tidal lagoons work in a similar way to...

tidal barrages by capturing a large volume of water behind a man-made structure which is then released to drive turbines and generate electricity

geothermal energy

refers to the thermal energy within the earth's interior

geothermal energy arises from...

heating deep within the Earth caused by the decay of radioactive material

geothermal energy is exploited from these sites by....

injecting water deep below the surface into the high-temperature rock, where it is heated to steam and brought back to the surface to power a turbine

nuclear energy

form of energy released from the nucleus, the core of atoms, made up of protons and neutrons. This source of energy can be produced in two ways: fission-when nuclei of atoms split into several parts-or fusion-when nuclei fuse together

nuclear reactors and their equipment...

contain and control the chain reactions, most commonly fuelled by uranium-235, to produce heat through fission

no alternative energy source is perfect but, in general, they have more positive attributes than negative

nuclear energy