GLOSSARY
The Climate Extremes Glossary is a comprehensive resource designed to help viewers deepen their understanding of the key scientific terms and concepts introduced in the documentary. This glossary breaks down complex climate terminologyand offers clear and concise explanations. Whether you're a student, educator, or simply curious about climate science, this section will provide valuable insights that enhance your learning experience and help you engage more fully with the film’s content.
THE CORRIDOR OF LIFE
GEOLOGICAL UNITS OF TIME
Eons, or Eonothems, are the largest division of time, lasting thousands of millions of years. These eons are the Phanerozoic (current eon) and the Precambrian eons of the Proterozoic, Archean, and Hadean.
Eras, or Erathems, are the subdivisions of eons. They are more on the scale of hundreds of millions of years. The eras are: Cenozoic; Mesozoic; Paleozoic; Neo-, Meso-, and Paleo-proterozoic; and Neo-, Meso-, Paleo-, and Eo-archean.
Periods, also referred as "systems", are the subdivisions of eras and typically last tens of millions of years. Some of the more famous epochs include the: Quaternary (current epoch), Cretaceous, Jurassic, Triassic, and Devonian.
Epochs, also referred to as "series", are the subdivisions of periods. Epochs tend to be a several million years in length. The current epoch is the Holocene. Many epochs are simply titled "Upper", "Middle", or "Lower" along with their period name (e.g. the Upper Triassic). "Upper" refers to the youngest part of the period and "Lower" refers to the oldest part of the period.
Ages, also referred to as "stages", are the smallest units of geologic time, and are usually only a few million years in length. The present age is the Meghalayan.
GEOLOGICAL EPOCH
Epoch, also referred to as "series", is a geological unit of time of several million years in length. The current epoch is the Holocene. Many epochs are simply titled "Upper", "Middle", or "Lower" along with their period name (e.g. the Upper Triassic). "Upper" refers to the youngest part of the period and "Lower" refers to the oldest part of the period.
QUATERNARY
The Quaternary period is divided into two epochs: the Pleistocene and the Holocene. The Pleistocene lasted from about 2.6 million to 11,700 years ago and was characterized by repeated glaciations. The Holocene began 11,700 years ago and continues to the present, marking a period of relatively stable climate and the development of human civilizations.
CORRIDOR OF LIFE
The Corridor of Life describes the range of temperatures thought to represent a “safe operating space” for humanity—approximately between -6°C and +2°C from the Earth’s average temperature of 14°C during the Holocene. Within this range, the Earth's self-regulatory capacity maintains thermal, freshwater, and biogeochemical conditions favorable for cultivated agriculture and stable human civilization.
ICE AGE
An ice age is a period of time where global temperatures drop so significantly that glaciers advance and encompass over one third of Earth’s surface both laterally and longitudinally.
INTERGLACIAL
An interglacial is a period of warmer global temperatures between ice ages, during which ice sheets retreat, sea levels rise, and ecosystems respond to a warmer climate.
PLEISTOCENE
The Pleistocene epoch is a geological time period that includes the last ice age, when glaciers covered huge parts of the globe. Also called the Pleistocene era, or simply the Pleistocene, this epoch began about 2.6 million years ago and ended 11,700 years ago.
MIKANKOVITCH CYCLES
Milankovitch cycles are natural, cyclic changes in the Earth’s orbit—including shifts in its eccentricity, axial tilt, and precession—that unfold over tens of thousands of years. They affect the amount and geographic distribution of solar energy arriving at Earth’s surface, resulting in long-term variations in Earth’s climate and influencing glacial and interglacial periods.
HOLOCENE
The Holocene is the name given to the last 11,700 years* of the Earth's history — the time since the end of the last major glacial epoch, or "ice age." This geologic epoch encompasses the entirety of recorded human history, and is the only period during which human civilization is known to have thrived.
TIPPING POINTS
9 PLANETARY BOUNDRIES
The 9 planetary boundaries are thresholds identified by scientists that define a safe operating space for humanity. Crossing these boundaries risks destabilizing Earth’s systems, which include climate change, biosphere integrity, and freshwater use.
The nine planetary boundaries identified are:
1. Climate change
2. Rate of biodiversity loss (terrestrial and marine)
3. Stratospheric ozone depletion
4. Ocean acidification
5. Interference with the nitrogen and phosphorus cycles
6. Change in land use
7. Global freshwater use
8. Atmospheric aerosol loading (microscopic particles in the atmosphere that affect climate and living organisms)
9. Chemical pollution
GREENHOUSE GASES
Greenhouse gases (GHGs) are atmospheric gases that trap heat within the Earth’s atmosphere, contributing to the greenhouse effect and global warming. Key GHGs include carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O).
EARTH'S SPHERES
Earth's spheres refer to the major components that make up the planet’s system: the atmosphere (air), hydrosphere (water), geosphere (land), biosphere (living organisms), and cryosphere (frozen regions).
INTERACTIONS AND FEEDBACK LOOPS
To be stable, all systems need to be self-regulating. Feedback loops permit systems to adjust their response to change (forcing factors) to return to stable conditions. A feedback is similar to a cause and effect loop, where information about a system is sent back to the system to improve its performance. Interactions and feedback loops in Earth’s systems are processes where a change in one component leads to changes in another, potentially amplifying (positive feedback) or dampening (negative feedback) the initial change.
LINETARY/LINEAR CHANGES
Linearity refers to changes that occur at a constant rate over time. In environmental science, linear changes are predictable and proportional to their driving factors.
NON-LINEARITY/NON-LINEAR CHANGES
Nonlinear changes occur when the rate of change varies and is not proportional to the initial conditions. These can lead to sudden shifts in ecosystems or climate systems, often associated with tipping points.
COMPOUNDING INTEREST
When interest is compounding, it means that when the next interest period arrives, it takes into account the total balance, rather than just the principal. For example, a $100 loan at 5% interest compounded annually will accrue a balance of $105 after one year. The next year, however, instead of taking 5% of $100, the interest will be applied to the total $105, making a new balance $110.25.
WATER VAPOR CAPACITY
Water vapor capacity refers to the maximum amount of water vapor that can be present in air when it is saturated (i.e., in a cloud). This quantity increases rapidly, by around 7% per 1°C, as temperatures increase. The rising water vapor capacity of air in warming world intensifies the hydrologic cycle, increasing both heavy precipitation and severe droughts.