Intended for healthcare professionals


When I use a word . . . . Some words about the climate

BMJ 2022; 377 doi: (Published 16 May 2022) Cite this as: BMJ 2022;377:o1222
  1. Jeffrey K Aronson
  1. Centre for Evidence Based Medicine, Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford
  1. Twitter @JKAronson

In October 2021 the Oxford English Dictionary incorporated 61 new terms, almost all of them dealing with aspects of ecology, and specifically climate change. The list included many compound terms, several including the word climate itself, such as climate action, climate catastrophe, climate crisis, climate denial/denialism/denier, climate emergency, climate justice, climate refugee, climate sceptic, and climate strike. Others dealt with capture and storage of carbon, ecological sustainability, and the availability of food or water. This influx of new terms into the dictionary to some extent mirrors the world’s preoccupation with greenhouse gas emissions. The UK contributes about 1% of global greenhouse gas emissions, of which about 76% is in carbon emissions, the rest coming from methane (16%), nitrous oxide (6%), and fluorinated gases (2%). The UK’s greenhouse gas emissions fell by 9.5% in 2020 compared with 2019; carbon emissions fell by 6% (from 1.01% of the global burden to 0.95%), a larger percentage fall than in most other countries in the world.

New words in the Oxford English Dictionary

What does it take for a newly coined word or phrase to make it into the Oxford English Dictionary (OED), or any dictionary for that matter?

The OED has some strict criteria.1 The rule of thumb is that a new word must have appeared in print at least five times, over a period of five years, in at least five databases that the lexicographers regularly consult. Many other dictionaries are less stringent.

Nevertheless, strict though the OED criteria are, many words meet them, and four times a year lists appear containing all the new terms and new meanings of existing terms that have been admitted to the dictionary during the previous quarter. For example, when I reviewed the new entries that were included in the list published in September 2021, I found 743 words and phrases, of which 30 were medically relevant.2

Unusually, in October 2021 the lexicographers included an extra tranche of new entries to the lists between the usual September and December tranches. The list was smaller than the usual quarterly tranches, only 61 entries in all, and in creating it the lexicographers’ attention was very firmly fixed on ecological matters.

The October tranche was organised in the usual way, in four separate lists:

1. Words completely new to the dictionary. This section (10 entries) included “CO2,” “global heating,” and a complementary pair, “energy from waste” and “waste to energy.”

2. New sub-entries. Compound words or phrases that are included under other headwords (38 entries). This section included three entries concerned with “carbon” and 11 with “climate,” plus “eco-anxiety,” “ecosystem service,” and “zero waste.” All but two of these entries were compound phrases.

3. New senses of old words. This section (13 entries) included “unsustainable” and “climate,” which, in this newly logged meaning, is technically a modifier “designating emotional or psychological states arising from concerns over the impact of climate change and global warming.” It also included the antonymic pair “clean” and “dirty,” referring to the amounts of pollutants produced by a source of energy.

4. Additions to unrevised entries. New senses, compound words, or phrases that were already included as draft entries, appended to the ends of existing entries, now fully incorporated (14 entries). These were also included in the other categories.

Items new to the dictionary do not have to have been recently coined—the dictionary is constantly catching up. The youngest entry in the October 2021 list was “climate strike,” first recorded in 2014. But the newly added term “extreme weather” was first recorded in 1576, 438 years before the most recently recorded example in 2014. It appeared in the 1576 revised edition of Actes and Monuments of these Latter and Perillous Days, Touching Matters of the Church (1573) by Bishop John Foxe, generally known as Foxe's Book of Martyrs. This is an example of a term that hasn’t changed its basic meaning (“weather that is very harsh, unseasonal, or atypical for a particular region”) but merits attention as having recently become particularly associated with a new phenomenon, namely the effects of climate change.


Although the first citation that accompanies an entry in the dictionary is usually the earliest identifiable example of the use of the word or phrase, it is occasionally possible to find earlier examples (antedatings). The new entry “decarbonization” refers to the reduction in carbon emissions that can be obtained by reducing or eliminating the use of fossil fuels. However, it has an older meaning, which the dictionary dates back to 1831, namely a reaction in which carbon is removed from a chemical; it has been used to refer to the processes that allow the elimination of carbon dioxide from the body via the lungs. For this meaning a minor antedating can be found from 1821, in The Medico-Chirurgical Review, referring to an 1816 presentation at a scientific meeting.3 I have seen what appear to be earlier instances still, but without enough evidence to date them exactly.

Words about climate

The word climate dominates the October 2021 list. There are 12 entries that include the word, and it is mentioned in definitions in two other cases, “eco-anxiety” and “extreme weather.”

The phrases that are given separate entries in which “climate” is used as a modifier are briefly described here:

● climate action: doing something about it

● climate catastrophe: severe adverse outcomes

● climate crisis: the risk of dangerous irreversible changes

● climate denial/denialism: rejecting the idea

● climate denier: one who rejects the idea

● climate emergency: the same as climate crisis

● climate justice: ensuring that doing something also addresses social justice

● climate refugee: someone who moves to a less severely affected place

● climate sceptic: the same as a climate denier

● climate strike: public protest to draw attention

It is odd that the compound nouns “climate denier” and “climate sceptic” are defined using exactly the same words, since the latter suggests doubt short of complete denial.

In addition to these, seven other compound nouns have been added that include the word “climate” as a modifier, terms that do not merit separate definition in the dictionary, their meanings being clear. They are climate anger, climate anxiety, climate depression, climate fear, climate grief, climate optimism, and climate pessimism.

The UK’s contribution to greenhouse gas emissions

I am constantly surprised that so few people know exactly what the UK’s contribution to global greenhouse gas emissions is. The usual estimate I hear when I ask the question is between 5 and 10%, although a few put it as low as 2%. The answer is 1%.4 The main culprits are China (30%), the USA (15%), India (7%), and Russia (5%); the EU as a whole contributes 9%.5 Carbon emissions comprise 76% of the total, methane 16%, nitrous oxide 6%, and fluorinated gases 2%.

UK emissions have been falling steadily since 1990, since when they have fallen by nearly 50%,6 the target set by the 2008 Climate Change Act being 80% by 2050.7 There was a large fall in greenhouse gas emissions in 2020, a 9.5% reduction from 2019, and our carbon emissions fell by 6% (from 1.01% of the global burden to 0.95%), a larger percentage fall than in most other countries in the world8; by comparison, India and China increased their emissions during the same time by 3%. However, much of our reduction was due to the pandemic, and we can expect there to be a rise when the next set of final figures is published.9

We are making large efforts to reduce our contribution to the global burden. That we should continue to do so there is no doubt, but we should not kid ourselves into believing that by doing so we are making a major contribution to the fall in global emissions. However, we are reducing our reliance on power supplies from abroad and we are also setting an example to the rest of the world.


  • Competing interests: We have installed solar panels on the roof of our house in Oxford; we run one hybrid car and one petrol-driven car, mostly using the former. We travel less than before but probably still too much. We have no idea what our greenhouse gas emissions are.

  • Provenance and peer review: Not commissioned; not peer reviewed


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