Part 4

Temperature Rise

Global Average Temperature Change for the Past 11,300 Years (Holocene)(Science, 8 March 2013: Vol. 339 no. 6124, pp. 1198-1201)

Temperature Anomaly (1880-2012)Baseline: 1951-1980

AerosolsAerosolsAerosolsAerosols

(tiny particles)Aerosols

Aerosols

Temperature Anomaly (1880-2011)Baseline: 1951-1980

Systematic Decadal Shift to Higher Temperatures Relative to 1951-1980

Temperature Anomalies from 1884 to 2011 Baseline = 1951-1980

Arctic Air Temperature Anomalies from Proxies (blue) and Observations (red)

Record High Temperatures in the U.S. are Increasing and Record Lows are Decreasing

Lead and lag.Carbon dioxide concentrations and averages of temperature proxy records for last deglaciation, as compiled by Parrenin et al.

E J Brook, Science, 2013;339:1042-1043Published by AAAS

Atmospheric CO2 and Global WarmingStabilization CO2

Concentration: Best Estimate (ppm)

Lower End (ppm)

Upper End (ppm)

Equilibrium Global Average Warming (°C)

280 ---- ---- 0

340 320 380 1

430 370 540 2

540 440 760 3

670 530 1060 4

840 620 1490 5

Earth’s Heat Gain During the Past 50 years (1021 Joules*)

• Oceans (0-2 km depth) = 245 (91%)• Continents = 10.4 (4%)• Earth’s Ice = 8.1 (3%)• Atmosphere = 6.6 (2%)

*A joule is a unit of heat energy

OCEAN HEAT CONTENT COMPARED TO TOTAL LAND, ATMOSPHERE AND ICE HEAT CONTENT.

What Global Average Temperatures Become Critical and Catastrophic for Humans?

• THE CURRENT BEST ESTIMATE IS 2° C (3.6° F) ABOVE PRE-INDUSTRIAL LEVELS IS CRITICAL. ABOUT 4° C (7° F) IS CATASTROPHIC. THE EARTH IS NOW 0.8° C (1.4° F) ABOVE PRE-INDUSTRIAL LEVELS.

• WHEN THE CO2 ABUNDANCE REACHES ~430 PPM THE TEMPERATURE ANOMALY WILL EVENTUALLY REACH 2° C. AT ~670 PPM IT WILL EVENTUALLY REACH A ~4° C.

• THE CURRENT ABUNDANCE (2013) IS 396 PPM AND RISING AT A RATE OF 2 PPM/YEAR, AND THIS RATE IS INCREASING. AT THE PRESENT ABUNDANCE THE TEMPERATURE WILL EVENTUALLY REACH 1.8° C.

• EVEN AT TODAY’S ABUNDANCE THE TEMPERATURE ANOMALY COULD REACH THE CRITICAL LEVEL BY THE END OF THE CENTURY. (ARMOUR AND ROE, GRL, 38, 2011; ARORA, ET AL., GRL, 38, 2011)

Probable Temperature Increases for “Low, Moderate and High CO2 Growth” (numerical data 2011)

Increase in Global Average Temperatures

2° C (3.6° F) Critical

3° C (5.4° F)

5.5° C (10° F) Catastrophic

WHAT IS CRITICAL AND WHAT IS CATASTROPHIC?

• CRITICAL --- serious drop in food production, serious water shortages, significant sea level rise (~1 m [3 ft]), political unrest, major drop in world economy, major animal extinctions and millions of human deaths. Third-world countries, e.g. Africa, are affected most, including large human migrations.

• CATASTROPHIC --- mass extinction event (>50% species extinction), major sea level rise, mass starvation, political and economic chaos, ~50% human deaths (>3 billion people). Probably the end of civilization as we know it today.