Global crop yield response to extreme heat stress under multiple climate change futures

Abstract

Extreme heat stress during the crop reproductive period can be critical for crop productivity. Projected changes in the frequency and severity of extreme climatic events are expected to negatively impact crop yields and global food production. This study applies the global crop model PEGASUS to quantify, for the first time at the global scale, impacts of extreme heat stress on maize, spring wheat and soybean yields resulting from 72 climate change scenarios for the 21st century. Our results project maize to face progressively worse impacts under a range of RCPs but spring wheat and soybean to improve globally through to the 2080s due to CO 2 fertilization effects, even though parts of the tropic and sub-tropic regions could face substantial yield declines. We find extreme heat stress at anthesis (HSA) by the 2080s (relative to the 1980s) under RCP 8.5, taking into account CO 2 fertilization effects, could double global losses of maize yield ( Y = −12.8 ± 6.7% versus −7.0 ± 5.3% without HSA), reduce projected gains in spring wheat yield by half ( Y = 34.3 ± 13.5% versus 72.0 ± 10.9% without HSA) and in soybean yield by a quarter ( Y = 15.3 ± 26.5% versus 20.4 ± 22.1% without HSA). The range reflects uncertainty due to differences between climate model scenarios; soybean exhibits both positive and negative impacts, maize is generally negative and spring wheat generally positive. Furthermore, when assuming CO 2 fertilization effects to be negligible, we observe drastic climate mitigation policy as in RCP 2.6 could avoid more than 80% of the global average yield losses otherwise expected by the 2080s under RCP 8.5. We show large disparities in climate impacts across regions and find extreme heat stress adversely affects major producing regions and lower income countries.

Differential climate impacts for policy-relevant limits to global warming: the case of 1.5 °C and 2 °C

“…As a consequence, the ISI-MIP protocol has been conducted with and without accounting for CO 2 -fertilization effects (further referred to as the CO 2 -ensemble and noCO 2 -ensemble, respectively). Recent findings also underline the importance of elevated temperatures and heat extremes (Gourdji et al, 2013;Deryng et al, 2014), ozone concentrations (Tai et al, 2014) as well as the potential of increasing susceptibility to disease as a consequence of elevated CO 2 levels (Vaughan et al, 2014) for agricultural yields, which may counteract potential yield gains by CO 2 -fertilization (Porter et al, 2014). Results for the CO 2 and noCO 2 -ensembles are presented separately, showing the range of potential manifestations and the additional risks of regional yield reductions, if effects of CO 2 -fertilization turn out to be lower than estimated by the model ensemble.…”

Traditional agriculture: a climate-smart approach for sustainable food production

“…Climate change also affects the invasive crop pest species (Yan et al 2017), livestock production (Rojas-Downing et al 2017) and aquaculture (Porter et al 2014). Tropical and developing countries are at the greater risk to climate change as compared to temperate and developed countries and this scenario encounters current and future food production (Gornall et al 2010;Hillel and Rosenzweig 2010;Deryng et al 2014;Porter et al 2014;Challinor et al 2014). …”

Organic Agriculture 3.0 is innovation with research

“…Nevertheless, humid temperate regions will be better off than semi-arid regions closer to equator, where the expected increased frequency of extremely warm periods and droughts will increase soil degradation and leave large areas unproductive. Intropic and subtropic regions, the consequences of warming and shifts in precipitation, are hard to foresee, and declines in crop yields are projected to range between 3% and almost total failure (Deryng et al 2014) Climate change will also affect the performance of semi-natural ecosystems such as pastures and the emergence, spread and distribution of livestock diseases, insect pests and invasive plant and animal species.…”