From A+ Club Lesson Planner & Study Guide


  • from Latin clima for "region, slope of the earth
    • from PIE *klei- "to lean"
    • so "climate" indicates weather patterns in different parts, zones or regions of the earth
  • climate is primarily related to distance from the equator
    • ancient geographers categorized zones by length of the day
    • by 1600s "climate" came to mean the general weather characteristics of a region, esp. regarding temperature, rainfall, winds, etc.

>> to do: combine w/ Climate change page >> probably best to separate into two articles Climate Outline and Climate Change Ouline

Climate classifications[edit | edit source]

Köppen–Geiger climate map (wikipedia)

Köppen-Geiger classifications[edit | edit source]

  • developed in 1884 by Köppen
    • revised bin 1918 & 1936 by Geiger
  • classifies by
    • seasonal precipitation
    • temperature patterns
Köppen climate classification scheme symbols description table (wikipedia)
1st Average Temperature Seasonal Precipitation 2nd 3rd
A (Tropical) every month of the year has average temperature at least 64.4 F or higher (18C+) significant f (Rainforest)
m (Monsoon)
w (Savanna, Dry winter)
s (Savanna, Dry summer)
B (Arid) No month with average temperature above 50.0 F or higher (10C) little W (Desert)
S (Steppe)
h (Hot)
k (Cold)
C (Temperate) Coldest month average temperature between 32F (0C) and 64.4F (18C)

and at least one month average temperature above 50F (10C)

Either dry winter or dry summer, with opposite wet season w (Dry winter)
f (No dry season)
s (Dry summer)
a (Hot summer)
b (Warm summer)
c (Cold summer)
D (Continental) At least one month average temperature below 32F (0C)

and at least one month average temperature above 50F (10C)

variable classes of seasonal rainfall, wet/dry seasons or no seasonal variation in rainfall w (Dry winter)
f (No dry season)
s (Dry summer)
a (Hot summer)
b (Warm summer)
c (Cold summer)
d (Very cold winter)
E (Polar) Every month has average temperature below 50F (10C) n/a T (Tundra)
F (Eternal frost (ice cap))

Trewartha climate classification[edit | edit source]

Climate periods[edit | edit source]

Pre-Modern human climate history[edit | edit source]

Modern humans period[edit | edit source]

Eemian[edit | edit source]

  • last inter-glacial period
  • 135,000 - 115,000 years ago
  • named for the warm-water sea mollusks whose fossils were found in the Eemian River in the Netherlands, demonstrating warm temperatures during this period.
  • characteristics
    • warmer & wetter in the northern regions
    • hippopotomus remains found along Rhine and Thames rivers
    • lower- Canadian Arctic had forests
  • ended with sudden cooling 114,000 years ago
    • sources
      • "Are We Holding a New Ice Age at Bay" by Matt Ridley, Wall Street Journal, Jan 14, 2012
      • Eemian (wikipedia)

965 AD[edit | edit source]

  • list of periods
    • The Holocene Warming a (11,600-8,500bp). The Egyptian Cooling (8,500-8,000bp). The Holocene Warming b (8,000-5,600bp). The Akkadian Cooling (5,600-3,500AD). The Minoan Warming (3,500-3,200bp). The Bronze Age Cooling (3,200-2,500bp). The Roman Warming (500BC-535AD). The Dark Ages (535-900AD). The Medieval Warming (900AD-1300 AD). The Little Ice Age (1300AD-1850AD). Recall that the Greeks survived the warmings without air-conditioners. "History," writes Plimer, "cannot be rewritten just because it does not fit a computer model with a pre-ordained conclusion." from

Climate change & cycles[edit | edit source]

new page to do: Climate History >> ?? Climate & Climate Change >> ?

>> add to Climate & Climate Change Outline


  • see this comment in WSJ article above b y Matt Ridley:

There are any number of things that can do it. Some of them have to do with the earth's orbit and orientation to the sun. These are cycles that play out in terms of 50,000 years at a time. Other cycles are much shorter. The sunspot cycle is 11 years. The AMO is 72 years (Atlantic Mutidecadal Oscillation), the ENSO is a similar cycle in the Pacific. The AMO is why we went down in temperature from the 1930s to 1970s. The longer de Vries cycle is a ~200 year oscillation in the sun's magnetic field. The sun basically rings magnetically like a bell with several "tones". One is 200 years long, one is 11 years long, there are others. Since roughly 1 CE, we have been dominated by some of the long tones of the sun. Aside from the magnetic effects which modulate the cosmic rays hitting the earth, the sun's spectrum shifts around into more or less UV. This has a lot of effect at the poles. Read the Svensmark I cited for one theory that seems to explain the long cycles due to the solar magnetic field. I am sure it will be refined over time, and I am sure other effects will be found, but it is one that seems to have legs in its predictive ability. On a shorter time frame with the AMO rolling over and heading down, the next 30 years will be cooler. See also the Wiki entry for this.