The rapid growth rate of coffee is maintained by 2500000 coffee farmers around the world.

Since the 1960s, the total output of coffee in the world has increased by three times every year, and the demand has increased by 5% a year. Such a rapid growth rate is sustained by 2500000 coffee farmers in the world, and 80 to 90 percent of them are small coffee farmers, and their coffee belt is also the region with the most significant climate change in the world.

Arabica is more sensitive to climate than the stronger Robusta. Almost all commercial Arabica coffee plants come from coffee trees growing in the mountains of Ethiopia, which limits its genetic diversity and makes it particularly vulnerable to climate change. In Mexico, for example, rising temperatures bring more rain, and a torrential rain may make it too late for plants to seed. In some dry places, the harvest of coffee is also severely challenged. In central Africa, the climate is getting hotter and drier, causing flowers to fall before they bear fruit. Even if the result is successful, the coffee beans will be dry and small. To make matters worse, the natural enemies of coffee plants are more adaptable to the hot climate, the first of which is leaf rust.

Leaf rust is the most serious coffee disease, and because of the rapid growth of market demand, many farmers choose to switch from traditional shade planting to sun planting in order to achieve rapid yield growth. But this is one of the main causes of large-scale outbreaks of coffee leaf rust on coffee farms in Central America and Mexico. Coffee leaf rust destroyed coffee trees from Mexico to Peru, with Central American countries hardest hit.

Climate change will affect any part of the coffee value chain. Due to too many uncertain risks, coffee farmers and coffee companies have to spend higher costs to control the quality of coffee. Including sea and land transport, global climate change will also bring great trouble to coffee transportation. As the cost rises, the cup of coffee in the hands of consumers may become more expensive

Although Robusta is one of the three major varieties of coffee, it shows very different characteristics: the same number of coffee beans contain twice as much caffeine as Arabica, and the main flavor is very similar to wheat tea, with lower sweetness. The Italians were the first countries to use Robusta. In addition, Vietnam and Malaysia are the most used countries, while in Taiwan, they are mostly used as commercial coffee.