Projections reveal the vulnerability of freshwater to climate change
Climate and land use changes are causing significant alterations in global terrestrial water storage, impacting extreme weather events such as floods and droughts, a Griffith University-led study has found.
Published in One Earth, the study investigated terrestrial water storage and projected future changes under three different future climate change and socio-economic scenarios:
1) a middle-of-the-road scenario with balance economic growth, moderate population and cautious energy use
2) a regional-rivalry scenario with competitive, region-focused societies, high energy use and moderate environmental concerns
3) a fossil-fueled-development scenario with rapid economic growth, a rising global population and a heavy reliance on fossil fuels
¡°Water from groundwater, rivers and rainfall is undergoing disruption in its natural cycle due to climate and land use changes, which disrupt patterns and amounts of rainfall and affect how water moves across the landscape,¡± said Dr Adeyeri Oluwafemi, lead author from the Australian Rivers Institute.
¡°Terrestrial water storage plays a critical role in human well-being affecting water supply sustainability and public welfare.
¡°Its deficit could lead to severe water shortages, food insecurity, habitat degradation, species extinction, and public tension.¡±
However, accessing long-term datasets needed to correctly understand water storage patterns is a challenge due to limited availability, monitoring infrastructure, and financial constraints.
¡°While direct observations provide a substantial amount of valuable information, the availability of such data is often restricted,¡± Dr Oluwafemi said.
Climate models have emerged as valuable tools for understanding long-term global-scale water budget in the form of precipitation, evapotranspiration, runoff, and storage changes.
However, Dr Christopher Ndehedehe, a co-author and an ARC Fellow at the Australian Rivers Institute said, ¡°The limitations in climate models for capturing fine-scale details and microphysical processes due to oversimplification of real-world features magnify their biases and make them unsuitable for the study of impact assessment.¡±
¡°Correcting these biases and investigating how well they mimic the signs of climate change is crucial.
¡°There is a critical need to understand projected changes in water storage characteristics by using climate model outputs and remote sensing observations to improve the accuracy of future projections of the amount of available freshwater.¡±
The findings from the study revealed how seasonal changes in climate factors affect water storage.
For example, shifting winds can impact moisture transport, leading to more frequent droughts or heavy rainfall, posing challenges for communities and ecosystems.
Correcting the biases in climate models reduced uncertainties, improving historical and future projections of water storage changes across all seasons.
As climate change modifies the global hydrological cycle, the distribution, amount, seasonal changes, and timing of water storage components such as runoff, precipitation, and evapotranspiration will likely change significantly.
Seasonal changes in winds that move across the earth affect how much moisture is carried from one place to another.
This can lead to areas experiencing more frequent droughts or heavy rainfall, causing problems for both people and the environment.