Climate and environment glossary – A–B

A–B | C–D | E | F–G | I–M | N–P | R–S | T–Z

1.5 degrees: the lower of the two targets to limit global average temperature increase set under the Paris Agreement. Climate scientists use ‘average global temperature rise’ as a way to measure how the climate has changed since the Industrial Revolution. They use computer models to test scenarios under different future climate conditions (see IPCC) so that the global community can set targets for global action to combat climate change. In 1997, when the first global treaty on reducing greenhouse gas emissions was agreed, the aim was to limit ‘global warming’ to no more than 2 degrees (2°C) above the pre-industrial level. By 2015, with a great deal more evidence available of climate change and its impacts the goal was to strengthen this to ‘avoid dangerous climate change by limiting global warming to well below 2°C and pursuing efforts to limit it to 1.5°C’.

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adaptation: communities, businesses, organisations, countries or regions making changes to ecological, social or economic systems in response to the actual or expected effects and impacts of climate change. Adaptations can range from building flood defences, setting up early warning systems for cyclones and switching to drought-resistant crops, to redesigning communication systems, business operations and government policies.


afforestation: creating new areas of forest on land that was not previously tree-covered. This is often promoted as universally positive (especially as a ‘carbon offsetting scheme’), but it is crucial to plant the right trees in the right places. For instance, a rush to plant fast-growing conifers on well-established peatland and heathland in the UK during the second half of the 20th century was ultimately halted once the true impact of damaging the existing peat bog carbon storage, or destroying rare or endangered habitats, was understood.

Anthropocene: an unofficial unit of geologic time, during which human activity is having a profound influence on climate and the environment. Many geologists and other scientists have suggested the Anthropocene began in 1950, when radioactive dust was widely scattered from nuclear bomb tests.

anthropogenic climate change: human-induced changes to the global atmosphere and therefore to global weather patterns via ‘global warming’, caused by burning fossil fuels and other practices that emit greenhouse gases (eg large-scale livestock farming, deforestation).


biodiversity: the biological variety and variability of life on Earth. Biodiversity tends to be measured by counting the number of species at the local level (eg by geographical region), but it can also be measured by assessing the number of genes in a given population. In 2017 scientists estimated that there are about 8.7 million species, but only around 1.2 million have been formally described.


bioeconomy: economic activity centred on harvesting renewable resources (in a sustainable manner) from land, fisheries and aquaculture environments and converting them into food and animal feed, or using them as raw materials for the pulp and paper industries and parts of the chemical, biotechnological and energy industries.

biomass/biofuel: organic material (biomass) such as certain crops, wood chips and animal waste, collected or grown specifically to be used as biofuels, either directly (eg woodchip-based heating systems) or indirectly (eg converted into ethanol or biodiesel). Biofuels are regarded as ‘renewable’ because they are quick to grow and they displace the use of fossil fuels that have been stored underground for millennia. They are sometimes also classed as ‘carbon neutral’ (taking in carbon dioxide from the atmosphere as they grow, then releasing the same amount when they are burned). However, this is controversial because some are grown on land suitable for growing food, and the vast quantities needed mean habitats are destroyed in favour of monoculture crops (eg miscanthus). There are also significant implications for water resources.

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bioregion: a region defined by characteristics of the natural environment, such as mountains and bodies of water, rather than by human divisions such as political boundaries.

biosphere: the ‘zone of life on Earth’, also known as the ecosphere (ie the sum of all ecosystems of the world).

birthstrikers: a movement of women who have chosen not to have children as a protest in response to the climate crisis and perceived collapse of civilisation.

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