Data from: A model-based evaluation of the effects of irrigation expansion on regional and global land surface climate

Irrigation is essential for enhancing agricultural productivity and
satisfying global food demand. The challenge of feeding a growing
population without increasing cultivated land can be addressed partly by
expanding irrigation into currently rain-fed croplands. At the same time,
water-scarce regions with currently unsustainable irrigation practices may
experience a reduction in irrigated area. While the evaporative cooling
effect of irrigation on regional climate has been extensively studied, it
is still unclear how different irrigation expansion (or contraction)
scenarios would affect global and regional near-surface climatic
conditions. Here we evaluate the hydro-climatic impacts of several
irrigation expansion scenarios. To assess changes in evapotranspiration
(ET) and land surface temperature (LST) under various irrigation
scenarios, we incorporated and validated an irrigation model representing
four main irrigation methods: sprinkler, drip, furrow, and flood-paddy,
into the NASA Catchment land surface model. Globally, the increase in ET
from irrigation and the associated impact on average yearly LST are
negligible, with an average global cooling of -0.03°C in the case of
current irrigation (with respect to a baseline without irrigation).
Compared to the current irrigation scenario, the maximum irrigation
expansion scenario can lead to an additional LST cooling of -0.01°C, while
the net irrigation contraction in a sustainable irrigation scenario is
associated with a 0.02°C warming. While global and regional impacts of
irrigation on LST are relatively modest, locally, the cooling effect can
be substantial, with a maximum yearly average LST cooling as strong as
-5°C and monthly cooling peaks of up to -10.2°C in heavily irrigated
periods.