Nearly a billion people will be affected by a scarcity of water by 2100, Northeastern researchers say – Northeastern Global News

Report on Projected Global Water Scarcity and its Impact on Sustainable Development Goals

Executive Summary

A recent analysis by researchers at Northeastern University, utilizing advanced Earth systems models, indicates a severe future for global water availability. The study, published in npj Climate and Atmospheric Science, projects that by the year 2100, declining runoff in the world’s major rivers will affect approximately 850 million people. This figure is more than three times the 260 million estimated by previous modeling efforts. These findings present a critical challenge to the achievement of multiple Sustainable Development Goals (SDGs), particularly those related to water, food security, energy, and poverty reduction.

Key Findings: A Worsening Outlook for Global Water Resources

Revised Population Impact Projections

The research forecasts a significant escalation in the number of individuals impacted by water scarcity. The primary findings include:

• An estimated 850 million people will experience the effects of reduced river runoff by the end of the century.
• This projection is based on the most skillful and recent generation of climate models (CMIP6), which show a more severe outcome than older models (CMIP5).
• The affected population is equivalent to more than 100 times the current population of New York City, highlighting the scale of the impending crisis.

Geographic Scope and River Basin Analysis

The study focused on the 30 largest and most significant river basins globally, which are vital for sustaining populations and ecosystems. The analysis revealed:

• Projections indicate that 40% of these 30 major river basins will exhibit decreased runoff by 2100.
• Key rivers included in the analysis are the Amazon, Congo, Ganges, Brahmaputra, and Nile, all of which support vast populations and critical agricultural systems.

Implications for the Sustainable Development Goals (SDGs)

The projected decline in river runoff directly threatens the global community’s ability to meet the 2030 Agenda for Sustainable Development. The impact cuts across several interconnected goals.

SDG 6: Clean Water and Sanitation

The core of the findings directly challenges the targets of SDG 6. Reduced river runoff compromises the fundamental availability of freshwater resources, undermining efforts to ensure universal access to clean water (Target 6.1) and implement integrated water resources management (Target 6.4).

SDG 2: Zero Hunger

River systems are the lifeblood of agriculture, recharging water supplies for irrigation and enriching soil with vital nutrients. A significant decrease in runoff will directly impact food production systems, threatening food security and the goal of ending hunger (Target 2.1) and ensuring sustainable food production systems (Target 2.4).

SDG 7: Affordable and Clean Energy

Many of the world’s major rivers are critical for generating hydropower. Reduced water flow will diminish the capacity for clean energy production, creating a significant obstacle for increasing the share of renewable energy in the global energy mix (Target 7.2).

Cross-Cutting Impacts on Other SDGs

• SDG 1 (No Poverty) & SDG 11 (Sustainable Cities and Communities): Water scarcity disproportionately affects vulnerable communities, potentially exacerbating poverty and threatening the resilience and sustainability of human settlements that depend on these water sources.
• SDG 13 (Climate Action): The study underscores the severe consequences of inaction on climate change. It also demonstrates that proactive climate policy can mitigate the worst outcomes.

Methodological Advancements and Scenario Analysis

Enhanced Modeling Skill

The study’s conclusions are based on a comparative analysis of two generations of climate models, revealing significant improvements in projection accuracy.

1. Model Comparison: Researchers compared the Coupled Modeling Intercomparison Project Phase 5 (CMIP5) with the more recent CMIP6, evaluating them against historical runoff data from 1960 to 2005.
2. Superiority of CMIP6: The CMIP6 models were found to be more skillful and accurate due to higher resolution, more comprehensive physics (incorporating land, ocean, and ice processes), and improved parameterizations for complex events like cloud formation.
3. Conclusion: The finding that these more skillful models project a worse future scenario lends greater confidence to the severity of the water scarcity threat.

The Role of Carbon Emissions in Water Availability

The research analyzed outcomes across five different carbon emission scenarios, directly linking climate action to water security and the SDGs.

• In a “greener world” with lower carbon emissions, the number of people affected by decreased water availability is projected to be 500 million.
• While this is a substantial reduction from the 850 million projected under higher-emission scenarios, it confirms that significant water availability challenges will persist even with robust climate mitigation efforts.
• This finding reinforces the urgency of pursuing aggressive emissions reductions as outlined in SDG 13 to minimize the impact on SDG 6 and related goals.

Conclusion for Policy and Scientific Communities

This research provides critical information for two key groups. For policymakers and water resource managers, the findings are a stark warning that necessitates immediate planning for adaptation and resilience in the face of declining water availability. For the scientific community, it validates the improvements in Earth systems modeling while highlighting the need for continued refinement. The clear link between carbon emissions and water scarcity provides further evidence for policymakers to accelerate the transition to a sustainable, low-carbon future in alignment with the Sustainable Development Goals.

Which SDGs are addressed or connected to the issues highlighted in the article?

• SDG 6: Clean Water and Sanitation

  The article’s central theme is the projected decline in river runoff and the resulting water scarcity affecting 850 million people. This directly addresses the goal of ensuring the availability and sustainable management of water.

• SDG 13: Climate Action

  The research explicitly links different carbon emission scenarios to the severity of water scarcity. It highlights that a “greener world” with lower emissions would reduce the number of people impacted, connecting the issue directly to climate change and the need for climate action.

• SDG 2: Zero Hunger

  The article mentions that river runoff is essential for enriching “agricultural soil.” A decline in runoff threatens agricultural productivity, which is fundamental to food security and achieving zero hunger.

• SDG 7: Affordable and Clean Energy

  The text states that river runoff is used to “generate hydropower.” Reduced runoff would therefore negatively impact the availability of this key source of renewable energy, connecting the issue to the goal of ensuring access to clean energy.

• SDG 9: Industry, Innovation, and Infrastructure

  The research itself, which uses advanced “Earth systems models,” “data science,” and improved “parameterizations” (CMIP6), represents an enhancement of scientific research and technological capability, which is a core component of this SDG.

• SDG 11: Sustainable Cities and Communities

  The article quantifies the affected population as being “100 times the size of New York City,” highlighting the massive scale of impact on human settlements that depend on major river basins for their water supply.

What specific targets under those SDGs can be identified based on the article’s content?

1. SDG 6: Clean Water and Sanitation

   • Target 6.4: By 2030, substantially increase water-use efficiency across all sectors and ensure sustainable withdrawals and supply of freshwater to address water scarcity and substantially reduce the number of people suffering from water scarcity. The article’s projection that “850 million people will feel the effects of declining runoff” directly relates to the goal of reducing the number of people suffering from water scarcity.
   • Target 6.5: By 2030, implement integrated water resources management at all levels, including through transboundary cooperation as appropriate. The study focuses on the “30 biggest river basins around the world, including the Amazon, Congo, Ganges, Brahmaputra and Nile rivers,” many of which are transboundary, making integrated management crucial.

2. SDG 13: Climate Action

   • Target 13.1: Strengthen resilience and adaptive capacity to climate-related hazards and natural disasters in all countries. The research aims to inform “policymakers and water resources managers” to help them understand impacts and inform adaptation strategies against the climate-related hazard of water scarcity.
   • Target 13.3: Improve education, awareness-raising and human and institutional capacity on climate change mitigation, adaptation, impact reduction and early warning. The study itself is a tool for raising awareness and building institutional capacity by providing better projections (“more skillful models”) for planning.

3. SDG 2: Zero Hunger

   • Target 2.4: By 2030, ensure sustainable food production systems and implement resilient agricultural practices… that strengthen capacity for adaptation to climate change, extreme weather, drought… The article’s finding that runoff decline affects “agricultural soil” implies a direct threat to sustainable food production, highlighting the need for resilient practices.

4. SDG 7: Affordable and Clean Energy

   • Target 7.2: By 2030, increase substantially the share of renewable energy in the global energy mix. The article notes that reduced river runoff will impact the ability to “generate hydropower,” a major source of renewable energy, thereby affecting this target.

5. SDG 9: Industry, Innovation, and Infrastructure

   • Target 9.5: Enhance scientific research, upgrade the technological capabilities of industrial sectors in all countries… The entire article is about a scientific study that improves climate modeling (“CMIP6” is more skillful than “CMIP5”) and uses “data science” to provide more accurate projections, directly contributing to this target.

Are there any indicators mentioned or implied in the article that can be used to measure progress towards the identified targets?

1. For SDG 6 (Clean Water and Sanitation)

   • Indicator 6.4.2 Level of water stress: freshwater withdrawal as a proportion of available freshwater resources. The article provides data for this by stating that “40% of the world’s 30 major rivers will exhibit decreased runoff by 2100,” which is a direct measure of change in available freshwater resources.
   • Number of people affected by water scarcity. The article provides a direct, projected metric: “850 million people will feel the effects of declining runoff,” which can be tracked against different emission scenarios (“500 million people” in a greener world).

2. For SDG 13 (Climate Action)

   • Level of accuracy in climate projections. The article implies this indicator by comparing the skill of different Earth system models (“CMIP5” vs. “CMIP6”) and noting that the “more skillful models are finding a worse future scenario.” Improvement in model accuracy is a measure of progress in understanding and preparing for climate impacts.

3. For SDG 7 (Affordable and Clean Energy)

   • Hydropower generation capacity. While not giving a number, the article implies that the ability to “generate hydropower” is an indicator that will be negatively affected by the “decrease in water availability,” thus impacting the share of renewable energy.

4. For SDG 9 (Industry, Innovation, and Infrastructure)

   • Advancements in scientific modeling. The article points to the use of “higher resolution,” “more intricate parameterizations,” and “comprehensive physics” in the CMIP6 models as concrete indicators of enhanced scientific and technological capability.

Table of SDGs, Targets, and Indicators

Source: news.northeastern.edu