Cities, Water And Climate Change

 Cities and urban centres house about half of mankind, with that number expected to reach three quarters of the world by 2050. By virtue of being some of the most populated areas on Earth, they are also by default the biggest consumers of both energy and water, and the biggest source of greenhouse gases.

Water is paramount for all living creatures. Specifically so, majority, if not all of land based species need freshwater to survive and thrive. This includes human beings, whose population recently hit the 8 billion mark. Now, about 70% of the Earth is made up of water, and of this, 97% is salt water. The remaining 3% is freshwater, and less than half of this, about 0.05% is in liquid form. The rest is locked up in glaciers, snow and ice.

Cities need a good amount of freshwater to function, and to serve the needs of the human populace, household use and all industrial activities undertaken within.

In terms of energy, all means of energy production and generation require water, and for the most part this is freshwater. Cities again, by virtue of their population and economic activities require considerable amounts of energy to run.

And about climate change, cities produce about 75% of all greenhouse gases. Buildings, industry, transport and domestic sectors all contribute a sizeable amount of these climate warming gases. The concentration of economic activity in these areas greatly affects air quality in addition to heating up the climate. Other ripple effects include worsening of human health.

Now, climate change will and is already impacting the water cycle which affects the availability of water, quality, quantity, access and supply while increasing demand. And again, climate effects are actually impacts of the hydrological cycle that is, too much or too little of water and often at the wrong times. Heatwaves, sea level rise, drought, cyclones, glacier melt, heavy rains and floods are all effects of water.

The overarching importance of water will become clearer in the coming years as climate continues to change

A city by the water. Photo(Emmanuel/iwaria)

When it comes to the nexus between climate change and water, cities have a big role to play.

First, in addition to population size, rural urban migration is increasing, especially in developing countries and this is especially young people looking for employment. Traditional means of earning a livelihood in rural areas like agriculture are under threat from climate change.

Two, most of these rapidly growing cities are experiencing uncontrolled and poorly planned settlements which are mostly informal. Water supply and access is not centrally run i.e. it’s not formally covered by the government. Most of supply is from private vendors whose health standards, safety precautions and legal credentials cannot be ascertained. Water provided here maybe illegally obtained which makes it harder to integrate into formal planning structures by local governments. It also means loss of revenue for these governments and a higher price for the end users i.e. it is expensive.

Protection of water sources maybe hard because of many sly connections (unmetered water), which opens them up to exploitation. A comprehensive governance structure for water from source, use, treatment and discharge back to water bodies is critical in order to correctly map out greenhouse gas emissions and subsequent steps for mitigation and adaptation.

The original plans for basic services and infrastructure are overstretched and unable to sustainably cover this increase in numbers. A crucial system that is either lacking or overworked is the wastewater system. Formal wastewater systems cover only the middle class going upwards. The biggest percent of city dwellers, those who live in slums, are left to their own devices. Wastewater and human waste (faecal sludge) are a big source of greenhouse gas emissions especially when untreated. The entire sector produces about 12% of methane and 4% of nitrous oxide, but when wastewater is discharged raw, it has three times the carbon footprint of processed wastewater. It also harms the environment through pollution and causing death of wildlife especially in waterbodies.

Therefore, cities including population planning and wastewater management in climate mitigation is crucial.

Treatment of wastewater has another benefit which is energy capture. Energy can be generated from methane and biogas and this used to plug the energy needs of a city.

Another important point is that most often these settlements and new development rapidly encroach on nearby ecosystems affecting their function and services, and causing environmental degradation. People will often build shanty towns in environmentally sensitive areas like right next to rivers and unstable hill slopes. This not only degrades this important ecosystems because of over extraction of water and raw sewage dumping, but also exposes residents to dangers such death and destruction of property due to heavy rains and flooding. Both of these can be caused by climate change. This is the same for building on slopy hillsides which exposes people to landslides during heavy rains.

Polluted rivers are a source of greenhouse gases. Climate change caused algal blooms can poison drinking water sources. Swelling lakes can swallow up lakeside cities.

Cutting down forests is another problem pertaining to cities and climate change. In many cases, new development i.e. infrastructure like roads and railways and new housing schemes are planned to be located in virgin territory as the city expands. This usually means the clearing of nature, vegetation and especially forests. Urban and peri urban forests are crucial for climate action. They also house a diverse array of wildlife and birds. Forests are super effective in absorbing greenhouse gases especially carbon dioxide. This gas is the biggest cause of global warming. They also enhance moisture circulation through evapotranspiration and also cool down the air through the same. This helps to counteract the urban heat island effect. Forests lower temperatures and are often as a source of shade and leisurely activities for city dwellers.

Poor air quality and heat stroke impact the health and life expectancy of city dwellers and lower their productivity and economic output.

Urban forests soak up excess water from heavy rains and flooding. They prevent soil erosion and landslides by holding soil particles closely together. They cover and enrich the soil by organic matter from decaying leaf and twigs. This enhances soil carbon quantities and together with the penetration of tree roots, increases percolation and infiltration of water into the ground, increasing groundwater flows and also mitigating climate. Cutting down forests increases run off which also washes away soil carbon, releasing it into the air and adding to climate change.

Forests are important for both mitigation and adaptation of climate change, of which cities are at the centre.

Mangrove forests help diminish the effects of tropical cyclones and storm surge arising from the sea. They protect seaside cities from sea level rise as well. These forests are extremely rich in carbon stores and their removal releases vast emissions into the air worsening climate change. Coastal cities should strive to protect and replant mangroves.

Cities depend on ecosystems farther up for drinking water supply. For the most part, rivers and springs have their sources in forests. Therefore, it is necessary for cities to involve all stakeholders in water governance because everything is interconnected. Communities and ecosystems farther upstream together with other end users of a water resource up to the sea need to be involved in consultations and discussions on proper water management. It is important to ensure equitable distribution of water along the entire chain from source to sea. Also, allocate enough water for different economic activities as well e.g. agriculture, urban use, fisheries, tourism, wildlife and ecosystem use throughout the entire water basin. This would help avert disagreements and conflict over water use.

An emphasis should be placed on conservation of water sources upstream. This means protection of forests from destruction e.g. banning deforestation and limiting encroachment while similarly encouraging reforestation. Additionally, ensuring equitable distribution of revenue from water use. That is, water removals from a rural source for urban use elsewhere should strive to make sure that these rural dwellers benefit economically in some way e.g. a city water utility firm can plant trees, maintain good quality roads for the community or provide employment for the local populace. This is benefits sharing.

All stakeholders in the water sector especially in cities – water basin management, water supply utilities, wwtps, users, forestry services and natural conservation, zoning and planning departments etc, should all be involved in water and climate change decisions. That is, decisions should not be taken in a stand-alone siloed manner. Everyone should be involved because water affects every sector.

Cities need an adequate supply of freshwater. This is either from surface or ground water. The costs of supplying drinking water, for example pumping, piping, treatment and distribution before consumption require energy of which most of it is climate polluting non-renewable fossil fuels. In fact, as both population and climate change goes up, demand for drinking water will lead to a 50% increase in energy use. This means more greenhouse gas emissions unless the sector is remedied through such actions as reuse and recycling of water, reducing wastage, policing and digitization to reduce theft and losses, as well as maintenance and turning towards clean energy sources such as solar and wind power.

Another important point on cites, water and climate change is the mismanagement of wetlands. Historically and to today, major cities are situated near freshwater sources. Ancient civilizations stem from having reliable freshwater to thrive. As cities expand, adjoining wetlands are usually the target and suffer. Wetlands including peatlands, marshes and swamps are some of the most effective terrestrial carbon sequesters. Their near-constant waterlogged nature ensures the absorption and non-release of carbon and methane for centuries. But often human development in the form of concrete and glass paves over these areas preventing them from functioning anymore. Water recharge is stopped because water cannot pass through concrete or glass at all. This impedes the ability of these natural carbon stores to act. The turning over of soil before construction releases a vast amount of stored carbon.

Wetlands are a source of clean drinking water and together with forests filter water from pollutants and sediments. Draining of wetlands release stored carbon too. This increases climate change and stresses water supply for cities.

A wetland. Photo(Aimee/iwaria)

In terms of energy, since energy production is impossible without water, more city growth means more water extraction. This places a demand on water which could affect other water reliant sectors too. In order to conserve precious water: pivoting to clean energy, better and eco-friendly building design, a network of green spaces and parks, making the best of sunlight for lighting and heating, green roofs and energy conservation can help lower (mostly fossil fuel) energy demand and thus cut water demand while cutting greenhouse gas emissions.

Another climate effect on water affecting cities is permafrost thaw. Permafrost is frozen subsoil in temperate and Arctic regions. It’s thawing because of global warming; affecting the integrity of structures like buildings and roads.

Now, all these water sectors especially the wastewater sector, drinking water supply, wetlands protection and nature based solutions i.e. forests would greatly benefit from measuring, monitoring and reporting of greenhouse gases. This could in turn be tallied and added to Nationally Determined Contributions (NDCs) and climate adaptation plans.

Awareness creation and education of interested parties and the wider public on the central importance of water and climate change in cities would help in a comprehensive and cohesive steps forward in creating thriving and equitable, healthy and resilient, ecofriendly and prosperous cities.

Capacity building and training will help supply and equip manpower with skills needed for water management throughout the entire chain.

Policy and regulation is a very important piece of the puzzle. Climate change, water, energy and development are interconnected and need to be looked at holistically. Involvement of experts including multi-disciplinary scientists and institutes and local and indigenous knowledge in drafting, enactment and execution of laws touching on this is highly beneficial. It is likely to be met with acceptance if public participation is carried out.

Protected natural areas next to a city can help combat climate change, absorbing its emissions.

Economic instruments like carbon emission trading schemes can incentivize the protection of water sources (because freshwater ecosystems absorb greenhouse gases) and climate friendly water management. The income can add to city or national coffers and be used for social welfare or conservation efforts.

Finance flows towards climate action should focus on water because it is a crucial element in especially mitigation but also adaptation.

Concerning loss and damage, water events such as floods and droughts destroy life and property. The new fund on this should look at this.

Political goodwill is the absolute necessity in climate action. Climate effects such as wildfires and sea level rise are connected to water and incidentally affect the entire globe in different ways. Cities are right in the middle of climate change and water, and elected leaders in all capacities would do well to recognize the importance of this.

Water scarcity especially drinking water can catch the political class flat footed and cause conflict, upheaval and changes in regime.

It is wise therefore to pay attention to cities, climate change and water.