Introduction
Climate change is a significant and complex issue that impacts various aspects of the environment and human society. This study note will delve into the topic of climate change, focusing on its effects on water, food, and energy supplies, as well as its broader impacts on ecosystems, human health, and vulnerable populations. We will also explore the feedback mechanisms and future projections associated with climate change.
Climate Change & the Water, Energy & Food Nexus
Impact on Water Supplies
Unpredictable Rainfall
Climate change leads to more erratic and unpredictable rainfall patterns, which can cause both floods and droughts. This unpredictability hampers water management efforts and affects the availability of freshwater.
Floods
Increased precipitation in some regions can lead to severe flooding. Floods can contaminate freshwater supplies with pollutants and sediments, reducing water quality.
Droughts
Conversely, other regions may experience prolonged droughts, reducing the availability of water for drinking, agriculture, and industry.
Rising Sea Levels
Rising sea levels, driven by the melting of ice sheets and glaciers, lead to saltwater intrusion into coastal freshwater aquifers, reducing the availability of potable water.
Melting Ice Sheets/Glaciers
The melting of glaciers and ice sheets has reduced freshwater storage by an estimated 3% since 1971. This loss is significant for regions that rely on glacial meltwater for their water supply.
NoteBy 2050, up to 5 billion people worldwide may face freshwater shortages, according to the UN.
Salinization of Groundwater
Saltwater intrusion due to sea-level rise is increasing salinization of groundwater at a rate of 10% annually, particularly in coastal areas.
Water Quality
Higher water temperatures, coupled with floods and droughts, can degrade water quality, making it unsuitable for consumption and agriculture.
ExampleIn the Sahel region, more frequent droughts have led to soil degradation and desertification, severely impacting food production due to a lack of water for irrigation.
Impact on Food Supply
Crops and Livestock
Increased temperatures and altered rainfall patterns affect crop yields and the availability of water for irrigation and livestock.
Declining Water Quality
Poor water quality can affect crop health and yields, while soil degradation and desertification reduce arable land.
Pests and Diseases
Warmer temperatures expand the geographic range of pests and diseases, further threatening crops and livestock.
ExampleClimate change is causing increased desertification, which impacts food production by reducing the availability of fertile land.
Impact on Energy Supply
Biomass for Energy
Fewer trees and vegetation due to climate change mean less biomass for energy production, especially in regions where people rely on fuelwood for heating and cooking.
High-Income Countries
While high-income countries like the USA and Australia also face water shortages, they are less likely to experience severe impacts on food and energy security due to their ability to import resources.
Global Impacts
Changes to Ocean Circulation
Melting ice caps and glaciers increase the freshwater input into oceans, altering ocean circulation patterns. This can affect global climate systems and marine ecosystems.
Impacts in Cold Environments
Melting Permafrost
Approximately 40% of permafrost areas are at risk of degradation, which can release methane, a potent greenhouse gas, into the atmosphere.
Sea Ice Decline
The extent and thickness of Arctic sea ice have declined, threatening the traditional lifestyles of indigenous peoples and ice-dependent animals.
Present and Future Impacts
- Present Impacts: Increased rates of glacial retreat, sea level rise, and permafrost melting.
- Future Impacts: Positive feedback loops, such as methane release from permafrost, further sea level rise, and changes in migratory patterns of birds and animals.
By 2050, only resorts above 1500 m may be able to offer snow for 100 days or more, impacting winter sports regions economically.
Exposure & Vulnerability
Vulnerable Populations
Certain groups are more vulnerable to the effects of climate change due to factors like location, wealth, age, gender, and education. These include:
- Mothers and babies
- Infants and toddlers
- School-age and older children


