Tea company above and below equator - they make big impact in tropics (8)

I believe the answer is:

typhoons

'they make big impact in tropics' is the definition.

'tea company above and below equator' is the wordplay.
'tea company' becomes 'typhoo' (UK tea brand).
'above and below equator' becomes 'ns' (north and south poles).
'typhoo'+'ns'='TYPHOONS'

(Another definition for typhoons that I've seen is " Tropical cyclones".)

I've seen this clue in The Independent.

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