Global climate change, exam 2

what is causing sea level rise

glaciers and ice sheets melting and adding water into ocean, volume of ocean expanding as water warms

how much carbon is land biosphere carbon

2100 GtC

what are the annual fluxes of carbon from the bioshpere

mostly from photosynthesis and respiration, in dynamic equilibrium 110-130 GtC, 1400 GtC from permafrost

how much carbon is stored within the ocean

mixed layer 900 GtC, deep ocean 37000 GtC

what are the annual fluxes of carbon from the ocean

co2 easily dissolves in water, mixed layer 60-80 GtC per year, deep ocean 100 GtC per year

how much carbon is currently stored in the atmosphere

885 GtC

what is the annual flux rate of carbon stored in rocks

0.1 GtC, volcanoes and chemical weathering

what is the alternative pathway for rock carbon exchange

via the biosphere, once living organisms die and become buried, humans then extract and burn to produce energy

how are humans interfering with the carbon cycle via rocks

fossil fuels burned, co2 and water vapor released into atmosphere 9.8x faster per year

how are humans interfering with the carbon cycle via land

land use changes add another 1.4 GtC per year

how are humans interfering with the carbon cycle via biosphere

taking in carbon 2.4x faster due to human activity leading to increased photosynthesis

how are humans interfering with the carbon cycle via the ocean

taking in carbon 3.2x faster, warming of water leads to higher solubility

according to the Mauna Loa observatory how much Co2 is in the atmosphere as of right now

429ppm

what is the solar constant in w/m2

1360 w/m2

define the solar constant

sun emits 380 septillion watts of power in all directions, it is distributed over a larger volume as you move further and further away

how much insolation is received at the top of the atmosphere on average in a location

340 w/m2

what percent of insolation received by the atmosphere is absorbed by earths surface

47%

what are the different fates of insolation

absorption by atmosphere, scattering/reflection, and transmission

absorption of insolation

atmosphere slightly warmed, different air molecules absorb different wavelengths of radiation

reflection of insolation

radiation makes contact with surface, reflected away without being absorbed, doesn’t produce heat in climate system, amount reflected relies on albedo, some radiation may be diffused

transmission of insolation

neither absorbed/scattered/reflected, directly transmitted through to surface

define radiative forcing

instantaneous change in energy balance for the planet caused by a forcing agent

define committed warming

unavoidable global temperature change that will happen due to earths energy budget still not being balanced

what are positive feedbacks

a process whereby an initial change sets off a chain reaction of events that reinforces that initial change, ice albedo, permafrost methane, and water vapor

define climate sensitivity

the estimated temperature response to changes in radiative forcing that incorporates feedback and time lags

define arctic amplification

the arctic is warming at about twice the average rate for the entire globe

RF of greenhouse gasses

co2, ch4, n2o, halocarbons, o3, stratospheric water vapor; overall positive

RF of aerosols

interact with sunlight/outgoing LW radiation, overall negative, sulfate highly reflective

RF of volcanoes

emit lots of sulfur aerosols directly into stratosphere, lifetime can be a few years, slight cooling for 2-3 years, negative

RF of carbon

dark soot leads to lowered albedo, positive

RF of mineral dust

wind blown dirt/sand, about 20% human, negative

how do we know that GHGs are the primary driver of climate change

emissions volume correlation, atmospheric oxygen trend, fingerprinting co2 source using isotopes

what is carbon fingerprinting

plants prefer carbon 12 over carbon 13, if burned plants will release carbon 12 rich co2, measure of annual c12/c13 ratio of atmospheric co2, decreasing ratio means co2 increase is coming from plant sources not volcanoes or oceans

how do we know that the sun isn’t the cause of rising temperatures

proxy records indicate changes in solar output amount to insignificant change of RF, stratosphere cooling, satellite measurements show no change between solar outputs and temperature

what is the urban heat island

areas tend to be warmer on average due to the built environment asphalt, metal, and tall buildings, dramatically changes albedo and latent heat flux

UHIs different from climate change

they are caused by land use cover changes but not GHGs, localized effect

UHIs relation to climate change

warmer global temps means warmer urban temps, cooling strategies can help pops adapt to warmer temps, disproportionate amount of GHG emissions from cities

what is the ozone hole

primarily caused by CFCs, human made chemical, once they reach stratosphere they release chlorine which breaks down leading to depleted area, causes increased UV-B radiation to surface

ozone relation to climate change

human activity leads to bad environmental impacts, CFCs both deplete and are a GHG

what is air pollution

introduction of directly unhealthy gasses or particulates into the atmosphere due to human activity, primary and secondary sources,

air pollution relation to climate change

some but not all are GHGs, both contribute to warming and health issues

how is the cryosphere a climate indicator

portion of earths surface where water is in solid form, matches temperature records, extent of melt and decreasing thickness is global

how are the ice sheets a climate indicator

cumulative changes in mass, antarctic and greenland, greenland decreasing much faster

how are sea levels a climate indicator

levels have risen 200m and rate of rising is increasing, now 4mm per year

how is humidity a climate indicator

rising primarily due to global temperature rise, atmosphere can hold more water vapor

what are some other climate indicators

change in season length, number of heating degree days v. cooling, shifting plant hardiness zone

how do clouds interact with the rest of the climate system

interact in 2 opposite ways with energy, reflective and insolating, tops reflect lots of incoming solar radiation, absorb heat energy trying to get out

how do aerosols impact clouds

act as condensation nuclei, water vapor condenses around to form water droplets, higher amounts lead to more smaller cloud droplets which changes the reflectivity of the cloud, remain higher in atmosphere

why are clouds so hotly debated among climate researchers

they are difficult to stimulate but highly important

how might clouds impact temperatures in the future

current research states positive feedback by 0.6 w/m2