Features International Sugar Journal

Take 2! How long before climate change makes sugar a rarity?

“All truth passes through three stages.

First, it is ridiculed.

Second, it is violently opposed.

Third, it is accepted as being self-evident.”

Arthur Schopenhauer

During the current summer, flooding, searing temperatures and raging fires across Europe, Asia and North America have brought home the stark reminder that climate change impacts have become increasingly prevalent with unwavering ferocity. The recently released sixth physical science assessment report (AR6) of the Intergovernmental Panel on Climate Change (IPCC) surveying the science of global warming, sounds the alarm louder. Average global temperatures are now 1.1°C above preindustrial records, and under every scenario for future greenhouse gas emissions that the panel examined, average warming of 1.5°C—a target set by the 2015 Paris climate accord—will very likely be reached within the next 20 years.

Climate models have improved since the last IPCC report enabling scientists to analyse current and projected temperature and hydrological extremes at a regional level and understand what global climate impacts will look like in different parts of the world. Modelling shows that the Arctic is warming faster than other regions and that high latitudes in the Northern Hemisphere are projected to warm by two to four times the level of global warming. While warming in the tropics is slower, it is noticeable because temperatures over land near the equator do not vary much year on year in the absence of human influence. The Gulf Stream is very likely to weaken over the century, according to the report. A complete collapse of the Atlantic Ocean current would disrupt regional weather patterns, weakening African and Asian monsoons and strengthening dry spells in Europe, scientists warn1.

Agricultural production is vulnerable to climate change owing to its sensitivity to weather parameters. “The changes in climatic events such as temperature and rainfall significantly affect the yield of crops. The effect of rising temperatures, precipitation variation, and CO2 fertilization varies according to the crop, location, and magnitude of change in the parameters. The temperature increase is found to reduce the yield, while the precipitation increase is likely to offset or reduce the impact of increasing temperature.”2

In their recent review, Malhi et al2 lists “A number of mitigation and adaptation strategies [that] have been developed to offset the deleterious impact of climate change on agricultural sustainability. These technologies include water-smart practices (laser land levelling, rainwater harvesting, micro-irrigation, crop diversification, raised-bed planting, direct-seeded rice), nutrient-smart practices (precision nutrient application, leaf colour charts, crop residue management), weather-smart activities (stress-tolerant varieties, ICT-based agrometeorological services), carbon-smart activities (zero tillage, legumes, crop residue management) and knowledge-smart activities (agricultural extensions to enhance capacity-building). These technologies significantly reduce the effects of climate change on crops, and make them more suited to the climate by minimizing the unfavourable impacts.”

In the editorial comment penned in December 2012, it was pointed out that “The challenges for the sugar industry are clear. Breeding cultivars that will be adaptive to heat stress and water stress, and are probably early maturing, is essential. In their own study, Derying et al3 noted by taking such adaptive measures, losses could be reduced by a factor of two for spring wheat and maize, and by 15% for soyabeans (Table 1).”

Table 1. Projected impacts on different crops without and with adaptation

  Without adaptation With adaptation
Spring wheat -14 to -25% -4 to -10%
Maize -19 to -34% -6 to -18%
Soyabeans -15 to -30% -12 to -26%
 

Source: Deryng et al (2011)

 

The unique feature of sugar is of course that it can be produced from both beet and cane, and this may be the industry’s saving grace against the throes of climate change. With beet requiring two-thirds less water than cane, and commercial seed breeders such as SES Vanderhave and Syngenta already supplying beet production technology to a few companies in the tropics, a start has clearly been made.

It will probably be some time before millers will have to relocate their factories or are rescued by plant breeders and the collective action worldwide to stem global warming. The cane sector in the meantime must do its part of shifting to green cane harvesting wholesale and dispense with burning.

Endnotes

1 https://www.climatechangenews.com/2021/08/09/five-takeaways-ipccs-2021-climate-science-report/

2 Gurdeep Singh Malhi, Manpreet Kaur and Prashant Kaushik (2021) Impact of Climate Change on Agriculture and Its Mitigation Strategies: A Review. Sustainability 2021, 13, 1318. https://doi.org/10.3390/su13031318

3 Deryng, D., Sacks, W. J., Barford, C. C., & Ramankutty, N. (2011). Simulating the effects of climate and agricultural management practices on global crop yields Global Biogeochemical Cycles, 25(2), 1–18. doi:10.1029/2009GB003765