Mid-summer, Northern hemisphere

Because the Earth is tilted on its axis, the length of the day (i.e. the time

between sunrise and sunset) changes throughout the year.

During summer in the northern hemisphere the North Pole is tilted

towards the Sun and days are longer and warmer, and during winter the

North Pole is tilted away from the Sun and the days are shorter and

colder.

Equinox Equinox Mid summer,

northern hemisphere

The intensity of

insolation received

at any given

latitude can be

found using

Lambert’s Law.

Also,

the amount of solar

energy lost as it

comes through our

atmospheric gases

is strongly affected

(Beer’s Law) by the

thickness of the

atmosphere

through which the

energy must pass.

Insolation (for incoming solar radiation)

Abandoned ships near fishing town Moynaq in Uzbekistan in April 2008.

The Aral Sea, a once vast brackish terminal lake in

the heart of Central Asia, has been rapidly drying

since the 1960s. It had separated into four separate

waterbodies by September 2009.

The main causative factor until the 1960s was the

periodic westward diversion of the Amu Dar’ya, the

main influent river, towards the Caspian Sea by both

natural and human forces.

The post-1960 recession, however, was

overwhelmingly the result of unsustainable irrigation

development. The lake’s modern recession has

caused a broad range of severe negative ecological,

economic and human welfare problems.

Aral Sea

August 25, 2000 August 19, 2014

His aim was to devise formulas that would define climatic

boundaries in such a way as to correspond to those of the

vegetation zones (biomes) that were being mapped for the first

time during his lifetime.

In western North America it's easier to visit several biomes than in the

East. That's because the West is more mountainous, and it's possible to

pass through various biomes simply by traveling up mountain slopes;

traveling a few hundred feet upslope is equivalent, biologically speaking,

to going north overland for hundreds of miles.

In western North America, you simply find a high mountain and climb until the trees

almost peter out. Beyond the mountain's taiga, if the slope continues, there may be

treeless tundra, very much as in the arctic.

In eastern North America, to visit taiga, which is a swampy, coniferous forests consisting

mostly of pines, spruces and larches, one must travel deep into Canada

Northern Hemisphere

tundra flowers

shrub willow plants

tiaga

tiaga

tropical rainforest

tropical deciduous forest

deciduous forest

temperate deciduous forest

Savanna and Tropical Grassland

Savanna and Tropical Grassland

temperate grasslands of native Nevada

bluegrass

temperate prairie

chaparral

chaparral

tropical thornscrub forest

tropical scrub forest

The 110MW retrofit of SaskPower’s Boundary Dam coal-fired

power plant in Saskatchewan, Canada will trap around 1

million tonnes of carbon dioxide (CO2) per year. The captured

CO2 will be injected into nearby oilfields to enhance oil

recovery. The plant began capturing CO2 in September, 2016.

Eruption of Mount Pinatubo,

Philippines, on June 15, 1991

While sulfur dioxide

released in

contemporary volcanic

eruptions has

occasionally caused

detectable global

cooling of the lower

atmosphere,

the carbon dioxide

released has never

caused detectable

global warming of the

atmosphere.

The gray bars at the top correspond to periods when Earth's climate was relatively

cool; the white spaces between them correspond to warm modes.

CO2 levels have have fluctuated from about two to four times modern levels

with a dominant period of about 100 My.

No correspondence between pCO2 and climate is evident because the evident

100 My cycle of the pCO2 record does not match the longer climatic cycle.

Feb. 18, 2015, the Great Lakes were 85.4 percent ice-covered, just above the 85.2

percent on Feb. 18 the year before, according to the Great Lakes Environmental

Research Laboratory. With below-average temperatures predicted for at least the

next week, the lakes could approach the year before levels of 92.5 percent ice

cover, the second-highest level since records began in the early 1970s.

Periodicity: 100,000 years

The seasonal cycle of insolation (Q) at 65 N latitude based

on eccentricity 100,000-year cycle, obliquity (axial tilt)

41,000-year cycle, and precession 26,000-year cycle.

The scale on

the vertical axis

is change in

O18 content.

By the work of

Lisiecki et al

2005 and

Huybers 2007,

the next

glaciation is

fully developed

between

AD 55,000 and

60,000, with

the next

interglacial

20,000 years

after that.