Final answer:
The current state of global freshwater use is complex with limited accessible freshwater and increasing demand outpacing population growth. High costs of desalination and variable water footprints of products, along with pollution, are major contributors to the finite supply. Freshwater is used primarily in irrigation, public supply, and industry.
Step-by-step explanation:
Current Value of the Global Control Variable for Freshwater Use:
The overall freshwater use on a global scale is intricate, influenced by a myriad of factors involving consumption patterns, industrial usage, and geographic availability. While it is challenging to define a singular 'global control variable,' we can address the dynamics of freshwater usage and stress. It is important to note that freshwater constitutes only 2.5% of Earth's water, with a significant portion of it trapped in glaciers and icecaps. According to the research by Shiklomanov (1993), just 0.77% of the planet's total water volume is accessible for use. Financially the cost of providing sufficient freshwater through industrial desalination is prohibitively high—estimated at US$3 000 billion annually (Postel and Carpenter 1997).
Furthermore the global water footprint which includes the volume of freshwater utilized throughout the production chain varies significantly across products, particularly due to varying levels of meat consumption in diets. The increase in global water demand outstripping population growth is a significant concern, with major uses being irrigation (68%), public supply (21%) and industry (11%). Pollution and over-use exacerbate the challenges to our limited freshwater supply, where already over 1 billion people lack access to adequate freshwater globally. Ultimately the current value of the global control variable for freshwater use reflects the tension between the demand for freshwater and the finite, unevenly distributed supply, coupled with the associated economic and environmental costs.