Link to the article:
A global dataset for the projected impacts of climate change on four major crops [Archive]
From the article:
The overall effects of climate change on crop yields are negative, with the mean and median of −11% and −6.2% without adaptation and −4.6% and −1.6% with adaptation, respectively. The median per-decade yield impact without adaptation is −2.1% for maize, −1.2% for soybean, −0.7% for rice, and −1.2% for wheat, which are consistent with previous IPCC assessments. The median per-warming-degree impact is −7.1% for maize, −4.0% for soybean, −2.3% for rice, and −3.7% for wheat. [...] Maize consistently shows the largest negative impacts, while rice shows the least.
The climate change impacts by IPCC regional groups reveals that Europe and North America are expected to be less affected by climate change in the mid-century (MC) and the end-century (EC) than Africa, Central and South America, particularly for maize and soybean. Both positive and negative effects are mixed in all regions.
[...]
Adaptation potential averaged 7.3% in MC and 11.6% in EC, which is not sufficient to offset the negative impacts, particularly in currently warmer regions. Residual damages will thus likely remain even with adaptation, which is also supported by other lines of evidence.