quiz 4 ECC

forced climate responses

changes in Earth’s energy balance, either globally or locally

unforced variability

internal dynamics of the climate system. Interactions among components like the atmosphere, ocean, ice and land.

Radiative forcing

how much a particular climate forcing mechanism would change Earth’s energy balance if the climate system was not allowed to adjust to that forcing.

radiative feedback

• Some properties of the climate system affect the global radiation balance.

• If these properties change as Earth warms or cools, they can lead to further changes in climate

positive radiative feedback

Feedbacks that amplify the effect of the original forcing (snow/ice albedo, water vapor)

negative radiative feedback

Feedbacks that counteract the effect of the original forcing

climate sensitivity

the ratio of the change in global mean temperature to the radiative forcing

In situ

measurements made by instrumentation located directly at the point of interest and in contact with the subject of interest “in its original place or position”

Remote Sensing

measurements made by instrumentation located some distance away from the subject of interest

paleoclimatology

The interpretation of this “climate proxies” which are influenced by climate and leave a natural archive of past changes in climate

Sources of Paleoclimatic Data

• ocean sediments

• lake sediments

• glaciers/ice sheets

• ice cores

• tree rings

Instrumental Data

Multiple research groups have compiled records of global temperature using data from weather stations and sea surface temperature. (NASA, NOAA/NCEI, JMA, HADCRU)

proxy data

physical characteristics of the environment that can stand in for direct measurements

Effects of the Little Ice Age

• Many lakes and rivers in Europe froze over

• Ice in the Atlantic made shipping to Iceland and Greenland untenable

• Very cold winters → crop failure, famine, and population decline

• Glaciers advanced, destroying farmland and affecting some towns

Drivers of Last Millennium Climate Change

• Solar energy output

• Greenhouse gases

• Sulfate aerosols from volcanoes

• Changes in land use and land cover

Lateral Morraine

edges of glaciers

terminal moraine

bulldozer effect

Glacial erratic

rocks that are in places that they should not be

what causes ice differences (glaciation)

• earths orbit (gravitational pull)

• interactions with moon, Jupiter, and Saturn

• eccentricity

• tilt of earths axis

• precession of equinoxes

eccentricity

how elliptical or oval our orbit is around the sun

tilt of earths axis (obliquity)

• varies: less tilt = more ice, more tilt = less ice

• which lateral gets more sun

prescession of equinoxes

the wobble of the earths axis

continental drift/ plate tectonics

• split at the mid ocean ridge

• cause for why we not longer have Pangea

PETM

• mass extinction event

• carbon and oxygen isotopes

• caused by lots of carbon and higher temperatures

cretaceous climate

• everywhere was warmer than today

• higher sea levels = different types of plants and animals

• continental drift, right after Pangea, locations were different

snowball earth

• between 600 million and 1 billion years ago

• caused by reduction in atmospheric greenhouse gasses resulting from intensive rock weathering (sun was dimmer)

Kaya Identity

CO2 emissions depend on:

• population

• affluence

• energy intensity

• energy technology

carboniferous periods

where coal came from

Milankovitch

• Astronomical Theory of the Ice Ages

• believed that cold summers led to glaciation by allowing snow to survive into the next year.

Ice: temperature to volume comparison

• higher temp - lower ice volume

• lower temp - higher ice volume

• based on CO2

what did moraines show?

glacial evidence from the ice ages