Researchers have long been using impact studies to study the effects of climate change on cocoa growth. These studies mimic conditions predicted at the end of the century¹ such as higher levels of drought and higher levels of atmospheric CO₂.

Studies have shown that increased levels of CO₂ may help offset the negative effects of reduced water availability on the growth of cocoa, which means our chocolate bars are safe for now.

How Will a Changing Climate Impact Cocoa Production?

Cocoa, a key ingredient in chocolate is one of the most important perennial crops in the world. It has been estimated that global cocoa production will reach 4.7 million tons in 2017, with most of the cocoa (74%) grown in West Africa.^2,3

As global CO₂ levels continue to increase, from present levels of 400 ppm to 550-800 ppm at the end of the century, dry areas like West Africa are projected to become drier, with more frequent droughts. So far, not much research has been done to study the effects of increased levels of CO₂ and decreased water availability on cocoa and other tropical perennial plants grown.^1,4

In order to maintain a sufficient food supply, it is important to identify which type of plants may be best suited to new conditions and how plants will respond to climate change. To fully understand how changes in water availability and CO₂ caused by climate change have an impact on crop growth and food availability, Researchers usually grow plants in conditions that mimic the predicted atmospheric conditions at the end of the century.

Since CO₂ is the primary substrate for photosynthesis, increases in atmospheric CO₂ is also expected to increase the plants growth rates by an average of 38%. However, plant growth rates may reduce by reduced water availability but at the same time increased rates of photosynthesis usually improve water-use efficiency in plants, which means the negative impacts of reduced water availability could be alleviated by increased CO₂levels.^1,5

Studying How Increased CO₂ Impacts Crop Growth

UK Researchers have studied the combined effects of water deficiency and increased CO₂levels on the growth of cocoa and have reported that elevated levels of CO₂ lowered the negative effects of reduced water availability. The Researchers grew cocoa in greenhouse compartments with different water levels and CO₂ concentrations, and then measured the photosynthesis and growth rates of the cocoa plants. They discovered that in elevated levels of CO₂, the growth of cocoa plants increased by roughly 50% in both water-deficit plants and well-watered plants when compared to cocoa plants grown at ambient CO₂levels.¹

The UK team observed that climate change conditions indeed had a positive impact on cocoa growth, but the effects of other changes associated with climate change have not been fully studied yet. Further, climate change may have several implications for the growth of crops like cocoa including O₃ pollution, flooding, temperature changes and the impact of climate change on pests and diseases. However, the collective effect of all these factors is yet to be known.^1,5

CO₂ Sensors for Climate Change Impact Studies

Researchers investigating the effects of climate change on plant growth will require highly accurate CO₂ measurements. The UK Researchers used an Edinburgh Sensors CO₂sensor in their greenhouse to provide reliable and precise CO₂ measurements. As a customer-focused provider of high-quality gas sensing solutions, Edinburgh Sensors has been providing gas sensors to the research community since the 1980s.^1,6

The Guardian NG from Edinburgh Sensors

The Guardian NG from Edinburgh Sensors provides near-analyser quality continuous measurement of CO₂ concentrations. This sensor can operate in temperatures of 0-45 °C and relative humidity of 0-95%, and comes with the CO₂ detection range of 0 to 3000 ppm.

The Guardian NG from Edinburgh Sensors

These features make it suitable for use in conditions meant to simulate climate change scenarios. In addition, the Guardian NG can be easily installed as a stand-alone product in greenhouses to measure CO₂ levels.^4,6

Download the Guardian NG Brochure for More Information

Conclusions

Reduced water availability and increased levels of CO₂ are expected in cocoa growing areas by the end of the century as a result of climate change. Researchers studying the potential effects of these conditions on cocoa growth used impact studies to investigate the effects of increased levels of CO₂ and reduced water availability on the growth of cocoa plants.

The team observed that water shortages can be alleviated by increased levels of CO₂, leading to increased cocoa growth under climate change conditions when compared to present conditions. During their climate change impact studies, the Researchers used gas sensors from Edinburgh Sensors to accurately measure CO₂ levels.

References

1. Lahive F, Hadley P, Daymond AJ, ‘The impact of elevated CO₂ and water deficit stress on growth and photosynthesis of juvenile cacao (Theobroma cacao L.)’ Photosynthetica, 2017. https://doi.org/10.1007/s11099-017-0743-y
2. https://www.cnbc.com/2015/07/23/americans-eat-how-much-chocolate.htmlAccessed September 12^th, 2017.
3. https://www.icco.org/statistics/monthly-review-of-the-market.html Accessed September 12^th, 2017.
4. https://www.co2.earth/2100-projections Accessed September 12^th, 2017.
5. Gornall J, Betts R, Burke E, Clark R, Camp J, Willett K, Wiltshire A ‘Implications of climate change for agricultural productivity in the early twenty-first century‘ Philosophical Transactions B 365(1554):2973-2989, 2010.
6. https://edinburghsensors.com/products/gas-monitors/guardian-ng/ Accessed September 12^th, 2017.