The intensification of climate change, such as global warming, can cause serious damage to agriculture, which currently faces an adverse climate in regards to agricultural production.
Research indicates that the global temperature could rise by 1.5°C to 2°C this century if there is not a strong reduction in greenhouse gas emissions.
This scenario increases the chance of extreme weather events, including the frequency of heat waves and droughts on a global scale, which, for experts, can have major impacts on tea production.
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Impacts Generated by Climate Change on Tea Plants
Several impacts are already being seen due to climate change.
Among them, the main ones are certainly the reduction in productivity due to prolonged periods of drought and high temperatures. These periods harm the development of tea plants, as well as modify the quality of soils, especially in organic systems.
The best quality tea, according to the authors cited, is produced in a cool climate. In mountainous regions above 1000 meters, although the quality can be favored, the culture can be harmed in the productivity due to thermal insufficiency and the high cloudiness, which make the foliage development very slow.
In addition to the impacts caused directly by cultural issues, climate change still affects the parameters related to the post-harvest of leaves and flowers, thus affecting quality.
About 30% of food productivity is explained by climate variation. The other 70% is explained by inputs, fertilizers, genetics, and agricultural practices. That is, when we have a climate problem, productivity drops, no matter how much the producer has invested in technology.
Extreme weather events are responsible for 25% to 35% of agricultural price swings.
Temperature Increase
Rising temperatures, increasingly intense and frequent droughts, and major storms can result in crop failures, reduced production, and increased food prices.
Maximum daily temperatures above 32°C are responsible for the fall in agricultural production since they interfere with the phases of the phenological cycle of cultures and in the development of vital organs of the plants.
It is expected that around the year 2050 the productivity of most crops will suffer a sharp decrease due to excess heat.
Changes Concerning Rain
Drought periods, accompanied by heat, strong insolation, and low relative humidity in the middle of the rainy season or the middle of winter, can result in a greater need for irrigation.
As much as the tea plant is resistant to periods of drought, its productivity decreases, as well as its quality.
The amount and availability of water are very important factors for the culture of the tea plant.
On the other hand, the increased frequency of heavy rains and storms can cause serious problems, such as the flooding of cultivated areas.
The intense amount of rain also affects the root system of plants, causing erosion and gully. This causes a significant drop in tea productivity.
Difficulty of Planning
We also see a greater difficulty in planning for farmers, who no longer know what to expect from the previously balanced climatic seasonality. Extreme events bring unpredictability.
The increase in this instability, in turn, makes it difficult for producers to organize, who, despite already working with climatic risks, plan planting, harvesting, and raising animals based on a certain seasonality.
Weather is the least controllable factor in production. Producers already know that there is a natural and inherent risk to it. But with climate change, tea producers lose all ability to plan production.
Diseases and Pests
One of the effects of climate change on tea culture will also be the change in the disease scenario and its management, which will certainly have an impact on agricultural productivity.
Climate change may have direct and indirect effects on both the infectious agent and the host plants and the interaction of both.
Among the direct effects is the change in geographic distribution. With these changes, the cultivation zones will probably also change (decrease in the favorable cultivation area). Likewise, pathogens and other microorganisms related to the disease process will be affected.
Thus, in certain regions, new diseases may arise and others lose their economic importance.
Pathogens, especially those that infect leaves, show fluctuations in their occurrence and severity during the year, which are attributed to variations in meteorological conditions.
The increase in humidity, for example, during the growing season, may favor the increase in the production of infective spores. On the other hand, other diseases are favored by low humidity conditions.
Another example is the reduction of rainy days in summer, which can reduce the spread of several pathogens.
Changes Related to Tea Quality
The flavor and aroma of tea are generated by two factors. The metabolites generated by the plant along with post-harvest processing.
In the case of tea, secondary metabolites are responsible for the characteristics that tea drinkers love so much. The production of these secondary metabolites is closely linked to environmental factors.
The time when the tea is harvested is one of the most important factors, since the number of metabolites may not be constant during the year. Seasonal and environmental variations in the content of virtually all classes of secondary metabolites are reported.
Age and development of the plant, as well as the different plant organs, are also of considerable importance and can influence not only the total amount of metabolites produced but also the relative proportions of the components.
It should be noted that the effects of seasonality can be confused with metabolic changes under the control of the development process internally (hormonally) controlled by the plant, another characteristic that can be altered due to climate change.
Although the tea plant has adapted to an ideal habitat, the plants are often able to exist over a considerable temperature range.
The range in which annual, monthly, and daily variations in temperature occur is one of the factors that exert greater influence on its development, thus affecting the production of secondary metabolites.
Low temperatures have significant influences on secondary metabolite levels.
Critical physiological factors, such as photosynthesis, stomatal behavior, mobilization of reserves, leaf expansion, and growth, can be altered by water stress and, consequently, lead to alterations in secondary metabolism.
The effects of rainfall on vegetation must be considered concerning the annual index, its distribution throughout the year, its effect on moisture, and its joint effect with the water absorption capacity of the soil.
Tea is a plant adapted to an enormous variation in the intensity and amount of light incidence, but there is a growing concern about the effects of the increase in ultraviolet radiation, resulting from the depletion of the ozone layer.
Mechanical factors to which plants are susceptible, such as injuries, or even mere stimuli, caused by rain, hail, wind, sand, invasion by pathogens, and grazing by herbivores, can also influence the expression of secondary metabolism. As an example here we have the tea grasshopper, which improves the quality of the plant in general.
With climate change, these cycles will be affected.
Damage caused to plants by injury or attack by herbivores or pathogens often leads to a biochemical response, which reduces the acceptability of the organ or the whole organism to future attacks.
Some plants in response to insect feeding rapidly produce compounds that can significantly decrease the palatability of the plant or part of it.
As presented here, we can conclude that climate change will affect the secondary metabolism of tea plants, causing another type of beverage. Of course, plants will adapt, but this will lead to a considerable change in the aroma and flavor of different tea varieties concerning various environmental factors.
Conclusion
We can say that climate change will incredibly alter the entire structure of the tea production chain. From the plants, their productivity, and even the drink itself.
The planet has already warmed by 1.1°C since the industrial revolution. As a result, the Earth’s climate is unequivocally changing as a result of human action. Climate change already affects billions of people on the planet, especially the most vulnerable and poorest populations.
It is still possible to achieve a safe scenario for the future of the climate, with an increase of only 1.5 °C by the end of the 21st century, but this requires enormous efforts to reduce the emission and increase the sequestration of greenhouse gases from the atmosphere.
These are the main conclusions of the last three reports published between the end of 2021 and the beginning of 2022 by IPCC (UN Intergovernmental Panel on Climate Change) scientists. The reports make clear that climate change already has and will have an even greater effect on food production and health, with serious risks for the poorest and most vulnerable.
The tea plant is incredibly dependent on the environment, as are the regions where high-quality beverage is produced. Climate change will have an irreversible impact on the tea industry, modifying the quantity produced and especially the quality.
The featured image at the beginning of this post is from Yusufk53 of PixaBay.
