Climate Changes!

These figures show that although temperature increase with time is accelerating, the current cyclical post glacial period has likely not yet reached its peak temperature.

Current Era Temperatures for Two Time Periods, as Deviations from Averages.

The figure below is average decadal deviation from the average global temperature from 1880-2018, from various analytical sources.  The fact that the 1880-2018 decadal deviations are greater than zero indicates that warming is accelerating.   Note that the mean deviations for the 1979-2018 period is approx. 0.1C per decade (1C per century) vs. the 1880-2018 period also indicates acceleration.

Trends from Various Sources

Temperature Cycles, from Thousands of Years Ago

The charts below are from data by ice core sampling.   The first chart goes back 440,000 years, and is from ice core samples at various locations, showing deviations from present day temperature.  The first chart is from (Vostok) ice core samples in Antarctica, its units are in 1,000 year increments (kyr) before present (BP).  The second chart is from EPICA. The European Project for Ice Coring in Antarctica (EPICA) is a multinational European project for deep ice core drilling in Antarctica.

These charts show that earth is currently on an upswing of global temperatures.  They show that they may be expected to go higher, when compared to previous maxima.  Also notice that ice volumes decrease as temperature increases.  Looking at the two previous peaks at approximately 3C, the current peak we are currently at (approx. 1.5C, may be going have 1.5C more to go to maximum.

Supporting Information

In the climate change debate, the most important parameter is Surface Temperature. Usually annual average surface temperature, averaged over the planet is the topic.   Presently the annual average earth temperature is 15.7^oC = 288.7^oK = 60^oF. Often the degree (^o) symbol is dropped and only the unit C, K or F is used.

Temperature has been measured in three ways:

• Hundreds of thousands of years ago to the 18th century by ice core samples.
• From the 18^th century to the present by surface thermometers.
• From 1979 to the present from space by weather satellites.

 An ice core (see http://en.wikipedia.org/wiki/Ice_core ) is a core sample that is typically removed from an ice sheet, most commonly from the polar ice caps of Antarctica, Greenland or from high mountain glaciers elsewhere. As the ice forms from the incremental buildup of annual layers of snow, lower layers are older than upper, and an ice core contains ice formed over a range of years. The same samples also yield historic CO2 levels. Due to the indirect method of determination of temperature and the uncertainties in age of the layers, ice core temperatures have the poorest accuracy.

In earlier times, thermometers were the glass-liquid type, with alcohol (dyed red) or mercury as the liquid). Later electronic thermometers have also been used, including thermocouples, resistance thermometers, and solid state thermometers.

Since the oceans cover about 70% of the earth’s surface, sea surface temperature (SST) is very important.   See http://en.wikipedia.org/wiki/Sea_surface_temperature .   SST is presently measured by battery powered “floats”. These floats transmit temperature and salinity data, at various depths to 2,000 meters, to satellites. See http://www.argo.ucsd.edu/How_Argo_floats.html .

Satellites are the best method of thermometry for averaging large areas. Several countries have deployed climate satellites. These satellites are in a polar orbit (north-south), circling the earth twice a day, and taking data for segments of earth surface from 1^o longitude wide and 1^o latitude high. They measure temperature at various altitudes by infrared thermometry, see http://en.wikipedia.org/wiki/Satellite_temperature_measurements. Infrared thermometry includes very long wavelength infrared, or microwave radiation.