Begun by the British in the early 19th century, there are 850 tea plantations spread over 593,000 acres in the northeastern Indian state of Assam, accounting for most of the country's harvest of leaves used to brew traditional breakfast teas.
But tea production in Assam declined from 564,000 tons in 2007 to 487,000 tons in 2009, says the Assam Branch Indian Tea Association, an umbrella group of some 400 plantations. It estimates that for 2010, the crop will have dropped to 460,000 tons.
"This is clearly climate change and it is bound to have major impact on the tea industry," said Debakanta Handique, a climate scientist in Assam, The Guardian newspaper reports.
Rainfall in Assam has dropped by more than one-fifth in the past 60 years and the minimum temperature has increased by 1.8 degrees to 67.1 Fahrenheit.
"Climate changing is definitely happening," said Mridul Hazarika, the director of the Tea Research Association, which is conducting studies on how the changes are affecting tea production, Britain's The Independent newspaper reports. "It is affecting the tea gardens in a number of ways."
An increase in erratic weather is adding further stress to the tea plants, which last year received less sunlight because of heavy rainfall, TRA research indicates. Assam experienced an average of an hour less of sunshine each day during this past growing season, TRA says.
Heavier than usual rainfall last year meant the plants received less sunlight and oxygen, TRA says. The resulting wet and humid conditions led to an increase in pests, compounding production losses.
Changes in the quality of Assam tea is also concerning growers.
"There is a huge demand for Assam tea abroad, and this is due to its strong, bright flavor," said Sudipta Nayan Goswami, an Assam planter, the Guardian newspaper reports.
"The changes will sharply hamper the demand for this variety of tea abroad," he said, noting that the black tea no longer has its distinctive creamy, strong flavor.
The average price of tea in Assam could reach $4.02 per kilogram by April, from $3.35 a kilogram, said tea plantation giant McLeod Russel India, The Economic Times newspaper of India reports.
"We're at the thin edge where any inconsistency in weather or cropping pattern has an immediate spiking effect on prices," said Azam Monem, director of the company.