Bringing Heat

Greenhouse gases trap heat in the atmosphere by absorbing it. Without greenhouse gases, the mean temperature on Earth's surface would be 0°F rather than 59°F.

Over a century of mean temperature data plotted over time demonstrates the increasing rate of the rise.

The pace of change is immediately obvious, especially over the past few decades.
— Ed Hawkins

by Ed Hawkins, National Centre for Atmospheric Science

Humans have spiked a 40% increase in the atmospheric carbon dioxide concentration since 1750, the approximate outset of the industrial revolution.

Water vapor, carbon dioxide, methane, nitrous oxide, ozone, and chlorofluorocarbons are the greenhouse gases in order of abundance in the atmosphere. The anthropogenic spike in greenhouse gases comes primarily from human activities (power generation, transportation, and industrial agriculture).

“Thus human beings are now carrying out a large scale geophysical experiment of a kind that could not have happened in the past nor be reproduced in the future. Within a few centuries we are returning to the atmosphere and oceans the concentrated organic carbon stored in sedimentary rocks over hundreds of millions of years.”
― Bill McKibben

REFERENCES

• 2015 Shatters Hottest Year Mark; 2016 Hot on its Heels? by Andrea Thompson, 20 January 2016, Climate Central.
• Greenhouse Gas, Wikipedia.
• HadCRUT4.4, Temperature data from Jan 1850 – Mar 2016.
• Spiralling global temperatures, Ed Hawkins, Climate Lab Book.
• See Earth's Temperature Spiral Toward 2°C, by Andrea Thompson, 11 May 2016, Climate Central.
• The Global Warming Reader: A Century of Writing about Climate Change, Bill McKibben, OR Books 2011.

The Anthropocene

Anthropocene word origin

Anthropocene is a 21st century term popularized by atmospheric chemist and nobel laureate Paul Crutzen for what will perhaps be recognized as a new geologic epoch.

The roots of the word are anthropo- for man and cene for new.

No date is recognized as the start of the Anthropocene, but atmospheric data seems to point to the early 19th century industrialization that occurred during the time of the Industrial Revolution. Other scientists indicate it should start with the Atomic Age of the 1950s.

The Anthropocene was preceded by, or is encompassed by, the Holocene which, in turn, was preceded by the Pleistocene

The Holocene began about 11,700 years ago and includes the growth of the human species. The Pleistocene lasted from about 2,588,000 to the Holocene and spanned the most recent period of repeated glaciations.

Shanghai at sunset

The Anthropocene is marked by the characteristics of:

• over-population (fourfold increase in the 20th century alone);
• the greenhouse effect;
• warming temperatures;
• melting glaciers;
• rising sea levels;
• frequent weather extremes; and
• overall climate disruption.

All of these characteristics are widely held to be linked to human activities.

"Two billion years ago, cyanobacteria oxygenated the atmosphere and powerfully disrupted life on earth. But they didn’t know it. We’re the first species that’s become a planet-scale influence and is aware of that reality. That’s what distinguishes us."
— Andrew Revkin

REFERENCES

• Anthropocene, Wikipedia.
• Coping with the anthropocene: How we became nature, De Gruyter, ScienceDaily, 17 March 2015.
• What is the Anthropocene and Are We in It?, Smithsonian Magazine, January 2013.