Okay, climate change is now getting serious with global warming set to impact on the enjoyment of a nice strong cup of Assam tea or a good brew of Columbian coffee. Already the subtle flavors of Assam tea are starting to change. For the tea and coffee connoisseurs in the developed world we might find the price increasing on that skinny latte or cup of tea.

While we might bemoan subtle favor changes or price rises from the comfort of our street cafes and comfortable dwellings, the real hardship will be felt by the thousands of small growers in the developing world. Those who are dependent on tea or coffee as a major cash crop and boost to their local economies face the problems of increasing temperatures and changing rainfall patterns.

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Flavor of Assam tea Changing

According to a report in The Guardian the cultivation of Assam tea in Northern India is being affected by global warming. Yields are reducing due to rising temperatures which is altering the flavor of highly distinctive and sort after Assam tea.

Mridul Hazarika, director of Tocklai Tea Research, identified rainfall and minimum temperature as two of the most important factors affecting both quality and quantity of harvests. "The decline has been taking place although there has been an increase in the area of tea cultivation as new gardens have come up, and many gardens have added new areas for tea plantation. This is an indication of the seriousness of the threat," said Hazarika in the Guardian report.

"Changes have already been observed in the flavor, but it is not possible to blame only climate change for this," he said. "Other factors like the fertilisers used and cultivation methods might also be partly responsible."

Changes in rainfall and increasing temperatures have also affected tea production in Sri Lanka and other tea producing regions. In the first three months of 2010 tea production from Sri Lanka fell by more than 41% - the largest drop in a decade. This produced a shortage of tea on global markets in early 2010 pushing up consumer prices.

Coffee and climate change

Meanwhile, scientists from the Centre for Ecological Sciences at the Indian Institute Science have forecast that over the next two decades, the quality and quantity of coffee beans grown in India's southern states will suffer, and costs will escalate. The trend for rising temperatures and changes in rainfall patterns projected by Asian and Indian monsoon models indicate problems for plantation coffee production.

The two main species of coffee - Arabica and Robusta - grow in slightly different but narrow climatic bands. Arabica evolved in the Ethiopian highland forests with a dry season and an optimum temperature range between 15 °C and 24 °C, and rainfall between between 1500 and 2000 mm per annum. Robusta evolved in the African lowlands in areas with abundant evenly distributed rainfall through the year of around 2,000 mm per annum, optimum temperature ranges from 22 °C to 26 °C, and at altitudes ranging from sea level to about 800 metres. Robusta is less tolerant of very high as well as very low temperatures than is arabica.

Many coffee growers are small landholders with coffee being a major cash crop grown in the tropics from Africa to the Caribbean, South America, India and south east Asia. These landowners will need assistance in managing the threat of climate change through adapting agricultural practices, and sometimes diversifying into other crops. Reducing carbon emissions from coffee growing and earning carbon credits for reforesting coffee lands under the Clean Development Mechanism or REDD scheme may provide further transfer of wealth to the first world through subsidising carbon emissions in developed countries.

Stimulated by warming climate conditions, the coffee berry borer, has also become a huge problem destroying coffee crops in most coffee growing regions of the world.

A paper on Climate Change and the Coffee Industry (PDF) published by the International Trade Centre in February 2010 outlines the climate risks for coffee:

Rising temperatures are expected to render certain producing areas less suitable or even completely unsuitable for coffee growing, meaning production may have to shift and alternative crops will have to be identified. Incidences of pests and diseases will increase whereas coffee quality is likely to suffer, both factors that may limit the viability of current high quality producers. More coffee may need to be grown under irrigation, thereby increasing pressure on scarce water resources. All the foregoing will increase the cost of production whereas in the future fewer parts of the world may be suitable for coffee production. If so then the already evident growth in concentration could become even more pronounced, bringing with it an increased risk of high volatility. For example if an extreme event should severely curtail the output of one of the major producers.

So for us privileged consumers in the western world climate change will also hit us in our little luxuries: in our habitual consumption of tea and coffee. As you sip your Orange Pekoe relishing the flavors, or skimming the froth from your capuccino, or knocking back that double espresso, understand that global warming will affect our lives in big ways and small.

We need to take mitigation and adaption actions in how we live our lives and our own carbon footprint, and urge our elected representatives to make the hard decisions for climate mitigation and adaption, and of course, support sustainable practices in tea and coffee production through getting behind Fair Trade campaigns.

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