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climate impacts, climate attribution, wheat, Kazakhstan, statistical yield model
Abstract:
Northern Kazakhstan is a major wheat exporter, contributing to food security in Central Asia and
beyond. However, wheat yields fluctuate and low-producing years occur frequently. It is currently
unclear to what extent human-induced climate change contributes to this. The most severe
low-producing year in this century was in 2010, which had severe consequences for the food
security of wheat-importing countries. Here, we present a climate impact attribution study that
quantifies the impact of human-induced climate change on the average wheat production and
associated economic revenues in northern Kazakhstan in the 21st century and on the likelihood of
a low-production year like 2010. The study uses bias-adjusted counterfactual and factual climate
model data from two large ensembles of latest-generation climate models as input to a statistical
subnational yield model. We consider the climate data and the yield model as fit for purpose as first,
the factual climate simulations represent the observations, second, the out-of-sample validation of
the yield model performs reasonably well with a mean R2 of 0.54, and third, the results are robust
under the performed sensitivity tests. Human-induced climate change has had a critical impact on
wheat production, specifically through increases in daily-minimum temperatures and extreme
heat. This has resulted in a decrease in yields during 2000–2019 by approximately 6.2%–8.2%
(uncertainty range of two climate models) and an increased likelihood of the 2010 low-production
event by 1.5–4.7 times (10th to 90th percentile uncertainty range covering both climate models).
During 2000–2019, human-induced climate change caused economic losses estimated at between
96 and 180 million USD per year (10th to 90th percentile uncertainty range covering both climate
models). These results highlight the necessity for ambitious global mitigation efforts and measures
to adapt wheat production to increasing temperatures, ensuring regional and global food security.
