Anthropogenic Global Issues

Vocabulary flashcards covering anthropogenic impacts on the environment, population growth metrics, biomass distribution, and key ecological threats mentioned in the lecture.

Anthropocene

A new geological epoch driven by the powerful impact of a single species, Homo sapiens, characterized by increased demand for energy, land, and water.

Background Extinction Rate

The natural phenomenon of species loss over time; the current extinction rate is estimated to be $100$ to $1,000$ times higher than this baseline.

The Great Acceleration

A unique event in Earth's history involving exploding human population and economic growth since the Industrial Revolution, with a significant explosion in growth starting in the 1950s.

$$Gt\,C$$

A unit of measurement standing for gigatons (billions of tons) of carbon, used to quantify global biomass distribution.

Terrestrial Vertebrate Biomass Ratio

The distribution of land-based vertebrate mass, of which humans and their livestock now account for $95\%$, while wild mammals represent a small fraction.

Quaternary Megafauna Extinction

An extinction event occurring between approximately $\approx 50,000$ and $\approx 3,000$ years ago that claimed around half of the large land mammal species ($> 40\,kg$).

Living Planet Index (LPI)

An indicator that tracks changes in the relative abundance of wild vertebrate species populations over time; it revealed a $73\%$ average decline between 1970 and 2020.

Tipping Point

The threshold in an environmental system where a significant and often abrupt change occurs, causing a major and potentially irreversible shift in the system's state or functioning.

Amazon Rainforest Tipping Point

A threshold where cumulative deforestation and biodiversity loss lead to fewer trees and less evapotranspiration, potentially releasing massive amounts of carbon and disrupting global weather patterns.

Atlantic Meridional Overturning Circulation (AMOC)

A large-scale ocean circulation pattern that, along with the subpolar gyre, is listed as a global tipping point that poses a grave threat to humanity if it collapses.

Habitat Loss and Degradation

The modification of an environment by removal, fragmentation, or reduction in quality, often driven by agriculture, logging, or development; it is the most reported threat to wildlife.

Species Overexploitation

Direct (hunting, poaching) or indirect (bycatch) harvesting of species at unsustainable rates.

Invasive Species

Non-native organisms that compete with native species for resources, act as predators, or spread new diseases in an environment.

Aurochs

An extinct wild cattle species; the last recorded live individual, a female, died in 1627, illustrating that biodiversity loss affects wild ancestors of domestic breeds.

Cavendish Banana

A single variety of banana that is responsible for $99\%$ of global exports, serving as an example of low agricultural biodiversity risk in food security.

Subpolar Gyre (SPG)

A circular current south of Greenland whose collapse would significantly change weather patterns in Europe and North America.

Pollution

A threat to biodiversity that directly makes an environment unsuitable for survival (e.g., oil spills) or indirectly affects food availability and reproductive performance.

Climate Change

A driver of biodiversity loss that causes species to shift their ranges and can confound signals for seasonal events like migration and reproduction.