These adjectives don’t seem to be confused very often — but it does happen, even in edited prose. And the more discussion there is of climate change (AKA climatic change), the greater the potential for mix-ups and malapropisms. My aim in this post is to emphasise the difference between the terms.
Climatic /klʌι’matιk, klə/ derives from climate. Climatical is a rare variant. A climatic event is generally a meteorological or geographical one, though figurative senses of climate (“prevailing conditions in a local environment”, e.g. political climate, climate of fear) may lead to corresponding uses of climatic. Here are some typical usages:
“This was a brief episode of climatic amelioration after the last glaciation” (The Nature of the Stratigraphical Record, 1984)
“The planetary seasons greatly determine temperatures and climatic patterns” (The Fate of the Dinosaurs, 1991)
“…what climatic change could mean for the flora and fauna of the British mainland” (New Statesman and Society, 1992)
“Climatically, the desert is violent” (Wheelbarrow across the Sahara, 1990)
The slightly more awkward climactic /klʌι’maktιk, klə/ has to do with climax, and hence is the form seen in the phrase anti-climactic. Climactical is a variant form. Climactic may have been coined analogously to syntax→syntactic (Burchfield 1998), and according to the OED (2007) was probably influenced by the related word climacteric. Climactic often appears in sporting and storytelling contexts:
“The final climactic day of golf’s Ryder Cup last week…” (Independent, 1989)
“In a thrilling climactic scene during a howling blizzard in the mountains, he and Umegawa do kill themselves” (Independent, 1989)
“…both he and Crecquillon anticipate Palestrina in the climactic use of great descending scales often in thirds, sixths, or tenths” (Concise Oxford History of Music, 1985)
“The Man in the Iron Mask climactically concludes the epic adventures of the three Musketeers” (Online-Literature.com)
The adverbs are climatically and climactically, respectively; an example of each concludes the selections of quotes above. Despite the infrequency of their occurrence, they too are sometimes confused. Below is an excerpt from Julian Jaynes’s The Origin of Consciousness in the Breakdown of the Bicameral Mind (Houghton Mifflin Company, 1990). The error occurs in the final sentence.
Because language must make dramatic changes in man’s attention to things and persons, because it allows a transfer of information of enormous scope, it must have developed over a period that shows archaeologically that such changes occurred. Such a one is the late Pleistocene, roughly from 70,000 B.C. to 8000 B.C. This period was characterized climactically by wide variations in temperature, corresponding to the advance and retreat of glacial conditions, and biologically by huge migrations of animals and man caused by these changes in weather.
(On the right is a photo of the same text. Click to enlarge it. I have used a longer quote to provide context, and because it relates to the development of language.)
To check that you have chosen the right word, bring to mind the morphological near-identity between climate and climatic: the overlapping climat- underlines their semantic connection. Or, as a mnemonic to help you remember the adjectival form of climax, think of the third and climactic act in a play.
Finally, if it is not too anti-climactic, I’d like to wish my visitors and readers a peaceful and happy 2010.