Skip to Main Content

Climate Crisis

This guide provides information, resources, and data on the climate crisis

The Anthropocene

The Age of the Humans

The term "anthropocene", is a combination of the Ancient Greek words: anthropos (meaning human) and kainos (meaning new or recent). Although the term had been described by scientists for decades, it wasn't until the year 2000, that Paul J. Crutzen, an atmospheric chemist, is credited with popularizing the term specifically to describe the human-behaviors that initiated an ecological shift characteristic of a new epoch.

A New Geological Epoch

On July 11, 2023, after 14 years of debate, the Anthropocene Working Group announced the last of their findings -- the "golden spike".

Crawford Lake (Milton, Ontario)

The dawn of a new geological epoch, the proof that humans have caused profound change to the planet, is found in the contaminated soil at the bottom of a quiet, pristine lake outside of Toronto. Year after year, particles settled onto the lake and drifted to its bottom, forming sediment layers that recorded environmental conditions much as tree rings do. Among the embedded contaminants are specks of fly ash— remnants from burning fossil fuels — and traces of radioactive plutonium from atmospheric nuclear bomb testing.

Three geological organizations must approve the choice for it to become the official marker.

A New Epoch?

In 2008, the Stratigraphy Commission of the Geological Society of London considered a proposal to make the Anthropocene a formal unit of geological epoch divisions; a majority of the commission decided the proposal had merit and should be examined further. Independent working groups of scientists from various geological societies thus set out to determine if and when the Anthropocene would be a new geological epoch.

The new epoch had no agreed-upon start date, with different scientists and teams proposing different events, ranging from the Neolithic Revolution around 12,000 years ago, to the Industrial Revolution and the invention of the steam engine in 1780, to the Trinity Test (first detonation of a nuclear weopon) on July 16, 1945.

A January 2016 report on the climatic, biological, and geochemical signatures of human activity in sediments and ice cores suggested the era since the mid-20th century should be recognised as a geological epoch distinct from the Holocene. The Anthropocene Working Group met in Oslo in April 2016 to consolidate evidence supporting the argument for the Anthropocene as a true geologic epoch. Evidence was evaluated and the group voted to recommend "Anthropocene" as the new geological epoch in August 2016.

In April 2019, the Anthropocene Working Group (AWG) announced that they would vote on a formal proposal to the International Commission on Stratigraphy, to continue the process started at the 2016 meeting. In May 2019, the Anthropocene Working Group (AWG) voted on the 2016 formal proposal to the International Commission on Stratigraphy, where they would make an official proposal by 2021. The AWG also voted in favor of a starting date in the mid 20th century.

The AWG identified twelve candidate sites for a Global boundary Stratotype Section and Point. One would be recommended as the Global boundary Stratotype Section and Point (GSSP) to define the base of the Anthropocene as a series (epoch) within the Geological Time Scale. Markers identifying this shift include radioactive isotopes, microplastics, heavy metals, and microfossils in marine, estuary, and lake settings.

  • East Gotland Basin (Baltic Sea) -- anoxic marine basin
  • San Francisco Estuary (USA) -- estuary
  • Searsville Lake (USA) -- lake
  • Crawford Lake (Canada) -- lake
  • Sihailongwan Maar (China) - lake
  • Flinders Reef (Australia) -- coral reef
  • West Flower Garden Bank (USA) -- coral reef
  • Antarctic Peninsula (Antarctica) -- ice sheet
  • Ernesto Cave (Italy) -- speleothem
  • Śnieżka Sudetes (Poland) - peatland
  • Beppu Bay (Japan) -- coastal marine basin
  • Karlsplatz (Austria) -- urban anthropogenic deposits

Climate Shifts

Climate change in a broader sense can also include the long-term changes to Earth's climate. Earth's climate alternates between ice ages and greenhouse periods.

  • An "Ice Age" is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers.
  • A "Greenhouse Earth" is a period during which no continental glaciers exist anywhere on the planet. Additionally, the levels of carbon dioxide and other greenhouse gases (such as water vapor and methane) are high, and sea surface temperatures (SSTs) range from 28 °C (82.4 °F) in the tropics to 0 °C (32 °F) in the polar regions. Earth has been in a greenhouse state for about 85% of its history
  • An "Icehouse Earth" is a state in which ice sheets are present in both poles simultaneously. The earth is currently in an icehouse state.

Within these major climatic periods, the earth fluctuates between glacial (interval of time within an Ice Age marked by colder temperatures) and interglacial (interval of warmer global temperatures between ice ages) periods, where the size and the distribution of continental ice sheets fluctuate dramatically. This fluctuation of the ice sheets results in changes in regional climatic conditions that affect the range and the distribution of many terrestrial and oceanic species.

Geological Time

Divisions of Geological Time
Geochronologic unit (time) Chronostratigraphic unit (strata) Time span Number of Defined Units Current Unit
Eon Eonothem Several hundred millions of years 4 Phanerozoic
Era Erathem Tens to hundreds of millions of years 10 Cenozoic
Period System Millions of years to tens of millions of years 22 Quaternary
Epoch Series Hundreds of thousands of years to tens of millions of years 38 Anthropocene
Subepoch Subseries Thousands of years to millions of years 11 Subatlantic
Age Stage Thousands of years to millions of years 96 Meghalayan

Highlighted Literature

Information & Resources