Thirty-eight years of CO<sub>2</sub> fertilization have outpaced growing aridity to drive greening of Australian woody ecosystems

Abstract. Climate change is projected to increase the imbalance between the supply (precipitation) and atmospheric demand for water (i.e. increased potential evapotranspiration), stressing plants in water-limited environments. Plants may be able to offset increasing aridity because rising CO2 increases water-use-efficiency. CO2 fertilization has also been cited as one of the drivers of the widespread ‘greening’ phenomenon. However, attributing the size of this CO2 fertilization effect is complicated, due in part to a lack of long-term vegetation monitoring and interannual to decadal-scale climate variability. In this study we asked the question, how much has CO2 contributed towards greening? We focused our analysis on a broad aridity gradient spanning eastern Australia’s woody ecosystems. Next we analysed 38-years of satellite remote sensing estimates of vegetation greenness (normalized difference vegetation index, NDVI) to examine the role of CO2 in ameliorating climate change impacts. Multiple statistical techniques were applied to separate the CO2-attributable effects on greening from the changes in water supply and atmospheric aridity. Widespread vegetation greening occurred despite a warming climate, increases in vapor pressure deficit, and repeated record-breaking droughts and heatwaves. Between 1982–2019 we found that NDVI increased (median 11.3 %) across 90.5 % of the woody regions. After masking disturbance effects (e.g. fire), we statistically estimated an 11.7 % increase in NDVI attributable to CO2, broadly consistent with a hypothesized theoretical expectation of an 8.6 % increase in water-use-efficiency due to rising CO2. In contrast to reports of a weakening CO2 fertilization effect, we found no consistent temporal change in the CO2 effect. We conclude rising CO2 has mitigated the effects of increasing aridity, repeated record-breaking droughts, and record-breaking heat waves in eastern Australia. However, we were unable to determine whether trees or grasses were the primary beneficiary of the CO2 induced change in water-use-efficiency, which has implications for projecting future ecosystem resilience. A more complete understanding of how CO2 induced changes in water-use-efficiency affect trees and non-tree vegetation is needed.

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Open Intellectual Property Models for Plant Innovations in the Context of New Breeding Technologies

Agronomy ◽

10.3390/agronomy11061218 ◽

2021 ◽

Vol 11 (6) ◽

pp. 1218

Author(s):

Michael A. Kock

Keyword(s):

Climate Change ◽

Food Security ◽

Intellectual Property ◽

Water Use Efficiency ◽

Water Use ◽

Open Innovation ◽

Climate Resilience ◽

Use Efficiency ◽

Mitigate Climate Change ◽

New Breeding Technologies

Plant related innovations are critical to enable of food security and mitigate climate change. New breeding technologies (NBTs) based on emerging genome editing technologies like CRISPR/Cas will facilitate “breeding-by-editing” and enable complex breeding targets—like climate resilience or water use efficiency—in shorter time and at lower costs. However, NBTs will also lead to an unprecedented patent complexity. This paper discusses implications and potential solutions for open innovation models.

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Effects of climate change and local environmental factors on long-term tree water-use efficiency and growth of Pseudolarix amabilis and Cryptomeria japonica in subtropical China

Journal of Soils and Sediments ◽

10.1007/s11368-020-02829-3 ◽

2021 ◽

Author(s):

Tengjiao Liu ◽

Yan Xu ◽

Zhihong Xu ◽

Hongbing Deng

Keyword(s):

Climate Change ◽

Environmental Factors ◽

Water Use Efficiency ◽

Water Use ◽

Cryptomeria Japonica ◽

Subtropical China ◽

Tree Water Use ◽

Use Efficiency

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Calcium and Potassium Nutrition Increases the Water Use Efficiency in Coffee: A Promising Strategy to Adapt to Climate Change

Hydrology ◽

10.3390/hydrology8020075 ◽

2021 ◽

Vol 8 (2) ◽

pp. 75

Author(s):

Victor Hugo Ramírez-Builes ◽

Jürgen Küsters

Keyword(s):

Climate Change ◽

Climate Variability ◽

Water Use Efficiency ◽

Water Use ◽

Agricultural Sector ◽

Regional Scale ◽

Adaptation Strategies ◽

Caribbean Region ◽

Coffee Production ◽

Use Efficiency

Coffee (Coffea spp.) represents one of the most important sources of income and goods for the agricultural sector in Central America, Colombia, and the Caribbean region. The sustainability of coffee production at the global and regional scale is under threat by climate change, with a major risk of losing near to 50% of today’s suitable area for coffee by 2050. Rain-fed coffee production dominates in the region, and under increasing climate variability and climate change impacts, these production areas are under threat due to air temperature increase and changes in rainfall patterns and volumes. Identification, evaluation, and implementation of adaptation strategies for growers to cope with climate variability and change impacts are relevant and high priority. Incremental adaptation strategies, including proper soil and water management, contribute to improved water use efficiency (WUE) and should be the first line of action to adapt the coffee crop to the changing growing conditions. This research’s objective was to evaluate at field level over five years the influence of fertilization with calcium (Ca+2) and potassium (K+) on WUE in two coffee arabica varieties: cv. Castillo and cv. Caturra. Castillo has resistance against coffee leaf rust (CLR) (Hemileia vastatrix Verkeley and Brome), while Caturra is not CLR-resistant. WUE was influenced by yield changes during the years by climate variability due to El Niño–ENSO conditions and CLR incidence. Application of Ca+2 and K+ improved the WUE under such variable conditions. The highest WUE values were obtained with an application of 100 kg CaO ha−1 year−1 and between 180 to 230 kg K2O ha−1 year−1. The results indicate that adequate nutrition with Ca+2 and K+ can improve WUE in the long-term, even underwater deficit conditions and after the substantial incidence. Hence, an optimum application of Ca+2 and K+ in rain-fed coffee plantations can be regarded as an effective strategy to adapt to climate variability and climate change.

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Water Deficit Modulates the CO2 Fertilization Effect on Plant Gas Exchange and Leaf-Level Water Use Efficiency: A Meta-Analysis

Frontiers in Plant Science ◽

10.3389/fpls.2021.775477 ◽

2021 ◽

Vol 12 ◽

Author(s):

Fei Li ◽

Dagang Guo ◽

Xiaodong Gao ◽

Xining Zhao

Keyword(s):

Gas Exchange ◽

Water Use Efficiency ◽

Soil Water ◽

Water Deficit ◽

Water Use ◽

Future Climate Change ◽

Leaf Level ◽

Fertilization Effect ◽

Use Efficiency ◽

Stimulation Of

Elevated atmospheric CO2 concentrations ([eCO2]) and soil water deficits significantly influence gas exchange in plant leaves, affecting the carbon-water cycle in terrestrial ecosystems. However, it remains unclear how the soil water deficit modulates the plant CO2 fertilization effect, especially for gas exchange and leaf-level water use efficiency (WUE). Here, we synthesized a comprehensive dataset including 554 observations from 54 individual studies and quantified the responses for leaf gas exchange induced by e[CO2] under water deficit. Moreover, we investigated the contribution of plant net photosynthesis rate (Pn) and transpiration rates (Tr) toward WUE in water deficit conditions and e[CO2] using graphical vector analysis (GVA). In summary, e[CO2] significantly increased Pn and WUE by 11.9 and 29.3% under well-watered conditions, respectively, whereas the interaction of water deficit and e[CO2] slightly decreased Pn by 8.3%. Plants grown under light in an open environment were stimulated to a greater degree compared with plants grown under a lamp in a closed environment. Meanwhile, water deficit reduced Pn by 40.5 and 37.8%, while increasing WUE by 24.5 and 21.5% under ambient CO2 concentration (a[CO2]) and e[CO2], respectively. The e[CO2]-induced stimulation of WUE was attributed to the common effect of Pn and Tr, whereas a water deficit induced increase in WUE was linked to the decrease in Tr. These results suggested that water deficit lowered the stimulation of e[CO2] induced in plants. Therefore, fumigation conditions that closely mimic field conditions and multi-factorial experiments such as water availability are needed to predict the response of plants to future climate change.

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Mediterranean irrigation under climate change: more efficient irrigation needed to compensate increases in irrigation water requirements

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-12-8459-2015 ◽

2015 ◽

Vol 12 (8) ◽

pp. 8459-8504 ◽

Cited By ~ 4

Author(s):

M. Fader ◽

S. Shi ◽

W. von Bloh ◽

A. Bondeau ◽

W. Cramer

Keyword(s):

Climate Change ◽

Irrigation Water ◽

Mediterranean Region ◽

Eastern Mediterranean ◽

Water Requirements ◽

Co2 Fertilization ◽

Fertilization Effect ◽

Co2 Fertilization Effect ◽

The Mediterranean ◽

Irrigation Requirements

Abstract. Irrigation in the Mediterranean is of vital importance for food security, employment and economic development. This study systematically assesses how climate change and increases in atmospheric CO2 concentrations may affect irrigation requirements in the Mediterranean region by 2080–2090. Future demographic change and technological improvements in irrigation systems are accounted for, as is the spread of climate forcing, warming levels and potential realization of the CO2-fertilization effect. Vegetation growth, phenology, agricultural production and irrigation water requirements and withdrawal were simulated with the process-based ecohydrological and agro-ecosystem model LPJmL after a large development that comprised the improved representation of Mediterranean crops. At present the Mediterranean region could save 35 % of water by implementing more efficient irrigation and conveyance systems. Some countries like Syria, Egypt and Turkey have higher saving potentials than others. Currently some crops, especially sugar cane and agricultural trees, consume in average more irrigation water per hectare than annual crops. Different crops show different magnitude of changes in net irrigation requirements due to climate change, being the increases most pronounced in agricultural trees. The Mediterranean area as a whole might face an increase in gross irrigation requirements between 4 and 18 % from climate change alone if irrigation systems and conveyance are not improved (2 °C global warming combined with full CO2-fertilization effect, and 5 °C global warming combined with no CO2-fertilization effect, respectively). Population growth increases these numbers to 22 and 74 %, respectively, affecting mainly the Southern and Eastern Mediterranean. However, improved irrigation technologies and conveyance systems have large water saving potentials, especially in the Eastern Mediterranean, and may be able to compensate to some degree the increases due to climate change and population growth. Both subregions would need around 35 % more water than today if they could afford some degree of modernization of irrigation and conveyance systems and benefit from the CO2-fertilization effect. Nevertheless, water scarcity might pose further challenges to the agricultural sector: Algeria, Libya, Israel, Jordan, Lebanon, Syria, Serbia, Morocco, Tunisia and Spain have a high risk of not being able to sustainably meet future irrigation water requirements in some scenarios. The results presented in this study point to the necessity of performing further research on climate-friendly agro-ecosystems in order to assess, on the one side, their degree of resilience to climate shocks, and on the other side, their adaptation potential when confronted with higher temperatures and changes in water availability.

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