The blistering afternoon sun beats down on my face. Normally by this time of day in May, dark clouds would be gathering, preparing for an almighty downpour. But there are no clouds in sight.
The lush-green, perfectly manicured tea plants extend as far as my eyes can see. Women wearing woven bamboo hats are dotted around the plantation, plucking leaves and putting them in baskets attached to their backs. The work looks gruelling in this heat.
And there's trouble brewing in the plantations of India's north-eastern state of Assam – the world's largest tea-growing region, famous for producing strong breakfast tea.
"We used to know when the rain would come," says Chandan Bora, manager of Tingkong Tea Estate. Sweat drips down his forehead as he gives me a tour.
"The changing climate has changed the crop pattern, which has led to uncertainty," he says. "With this change of climate, it will be difficult to sustain the industry."
Warmer temperatures and changing rain patterns affect the production and quality of the tea. Continuous rains, for example, lead to crop losses, and this year he expects little high-quality tea to be produced.
A warmer climate also helps pests to thrive and has led Bora to increase the use of pesticides and fertilisers, which means higher production costs – yet tea prices are not going up to compensate.
Heating upOver the past century, average land temperatures in Assam have increased by 1.3 °C and rainfall is down by 20 centimetres a year, says R. M. Bhagat, chief scientist at the Tea Research Association in Jorhat, Assam's tea hub.
He says that rainfall used to be evenly distributed, but in the past 30 years has become unpredictable because of an increase in the severity and frequency of extreme weather events. "Sometimes there's too much rainfall, and at other times not enough," he says. Too little rain forces planters to use sprinklers or irrigation pipes to get better yields, but those are expensive.
The change in climate is also conducive to pests such as tea mosquito bugs (Helopeltis theivora) infesting the plants' shoots. The invaders' eat foliage and infect the plants with diseases, thus lowering the yield, Bhagat says.
The use of pesticides and fertilisers has in turn increased, resulting in an increase in production costs and posing a potential risk to human health.
Experts say these changes have meant that the characteristics Assam tea is famous for – pungency and a full-bodied flavour – have changed.
Last year, the industry experienced an 8 per cent fall in tea exports, according to the Indian Tea Association. This cannot, however, be attributed wholly to climate change: the industry is also grappling with stagnant tea prices and stiff competition from Kenya and Sri Lanka.
Tea tacticsSo how are planters dealing with the changing climate?
Scientists in Assam are testing types of tea that can adapt and survive in hotter and drier conditions. "We are testing tea varieties in likely future scenarios: under elevated carbon dioxide and elevated temperature conditions using specialised equipment," Bhagat says. He can't tell me more because research is still in initial stages.
The Tea Research Association and the University of Southampton in the UK are also investigating impacts of climate change on tea production and livelihoods in north-east India.
Although this research is ongoing and the group is yet to complete its analysis, principal investigator Ellie Biggs of the University of Southampton tells me that in Assam, rain appears to have a more significant association with tea yield than temperature does. She says preliminary findings suggest that water-resource management could "play the most vital role in climate impacts on tea for this region".
Meanwhile, some tea planters have decided to increase vegetation cover and create more water bodies on vacant land within their plantation areas. It's a simple and cost-effective method.
"We need to micromanage in whatever way we can," says Sandip Ghosh, secretary of the Assam branch of the Indian Tea Association. "Green plants retain the moisture in the soil. You can't do any damage if you plant trees."
But despite efforts to counteract the effects of the changing climate, some in the industry are fearful that the day might come when Assam may no longer grow high-quality black tea.
A small number of the region's 800 plantations are already moving into producing white and green tea, for which they can fetch higher prices – leaving traditional black Assam varieties behind.
"Who can fight with nature?'" asks Bora. "We can't. The low quality of tea being produced is a real danger for the industry."