2017年8月18日 星期五

Global water crisis: is the world running out of fresh water?

⛈⛈⛈ Water crisis ⛈⛈⛈



This article discusses the global freshwater crisis, highlighting the increasing demands on freshwater sources due to rising populations and temperatures.
 
It illustrates various consequences of water scarcity such as depletion of aquifers, sinking of cities, and the potential for conflicts over water resources. It also presents examples of successful water management strategies implemented in countries like Australia and Israel, including water pricing, recycling, and desalination. Moreover, it explores alternative solutions such as rainwater harvesting and efficient irrigation techniques. The article emphasizes the urgent need for effective conservation measures to address the freshwater crisis.

The main factors contributing to the global freshwater crisis include increasing populations, rising temperatures leading to changes in precipitation patterns, and unsustainable water usage practices such as agriculture and energy production.

The depletion of aquifers impacts water availability by causing groundwater levels to drop, leading to decreased access to water for irrigation and domestic use. This is particularly evident in regions like India and California where aquifers are being drained faster than they can be replenished, resulting in water shortages.

Australia implemented successful water management strategies during the Millennium Drought, including putting a price on water and making it a tradable commodity. This incentivized efficient water usage and allowed for the transfer of water rights between users, helping to mitigate the impact of the drought.

Israel employs innovative methods such as recycling effluent water for agricultural use and desalination to address water scarcity. These measures have significantly increased water availability for agricultural purposes and reduced dependence on freshwater sources.

Desalination is considered a limited solution to the freshwater crisis due to its high cost, large energy footprint, and potential ecological impacts such as marine ecosystem disruption. While it may be feasible in wealthy regions, it is not a viable option for most of the world's population.

Rainwater harvesting contributes to water conservation efforts by capturing and storing rainwater for various purposes, including irrigation and domestic use. Examples provided in the article include efforts in cities like Singapore, Melbourne, and Manchester to incorporate rainwater harvesting into urban infrastructure.

Businesses can play a significant role in promoting water efficiency by implementing measures such as drip irrigation techniques, investing in water recycling technologies, and supporting policies that incentivize sustainable water usage.

If effective measures to conserve freshwater are not implemented globally, the consequences could include worsening water shortages, increased competition for limited water resources leading to conflicts, and negative impacts on ecosystems and biodiversity. Additionally, communities reliant on agriculture and other water-intensive industries could face economic hardships.

Given that 70% of the Earth’s surface is water, and that volume remains constant (at 1,386,000,000 cubic kilometres), how is a water shortage even possible? Well, 97.5% is seawater unfit for human consumption. And both populations and temperatures are ever-rising, meaning that the freshwater we do have is under severe pressure.

Water demand globally is projected to increase by 55% between 2000 and 2050. Much of the demand is driven by agriculture, which accounts for 70% of global freshwater use, and food production will need to grow by 69% by 2035 to feed the growing population. Water withdrawal for energy, used for cooling power stations, is also expected to increase by over 20%.