Environmental and Global Issues in Energy Use

Energy choices change the environment

Energy resources supply electricity, heating and transport, but obtaining and using them can affect the environment. A useful comparison asks what causes the impact and when it occurs. Burning a fuel can pollute the air; extracting it can disturb land. A resource that needs no fuel burned while generating electricity avoids those combustion emissions, but its equipment may still affect land, water or wildlife.

Fossil fuels and nuclear fuel: different problems

Burning coal, oil or gas releases carbon dioxide. As a greenhouse gas, carbon dioxide reduces the rate at which thermal energy escapes from Earth to space and contributes to global warming. Burning fuels that contain sulfur can also release sulfur dioxide, which contributes to acid rain. These are distinct effects: cutting sulfur dioxide would not, by itself, solve the carbon dioxide problem. Mining and drilling for fossil fuels can also damage landscapes, and oil spills can pollute water. Fossil fuels provide concentrated energy and are widely used, so reducing their use involves a real choice about how to meet demand.

Nuclear power stations do not burn fossil fuel while generating electricity, so they avoid fuel-combustion emissions during operation. Instead, they produce radioactive waste, some of which remains dangerous for thousands of years. An accident could release radioactive material and contaminate the surrounding area. Comparing nuclear and fossil-fuel power therefore involves different kinds of risk, not a single measure of ‘pollution’.

Renewable resources also have impacts

Wind turbines and solar panels generate electricity without burning fuel. Wind farms can affect land use, habitats and wildlife. Large solar installations can take up land and affect habitats; manufacturing some solar technologies uses hazardous materials. Hydroelectric schemes may flood land and change the landscape. These effects depend on the site and the technology, so they are not identical for every project.

Bio-fuels come from recently grown material and can be replenished, but burning them still produces air emissions. Growing or collecting the material can also affect land use. Whether a bio-fuel has a low overall environmental impact depends in part on how it is produced and replaced; calling it renewable does not make its use automatically harmless. Geothermal, tidal and wave resources likewise avoid burning fuel to obtain their energy, but their environmental impacts depend on the particular installation. Large-scale wave and tidal impacts are less well established than the effects of long-used technologies. Overall, renewable resources generally cause less harm than fossil fuels by many measures, but none should be described as having zero impact.

Interpreting global energy-use trends

A trend describes the overall direction of change over time. The textbook’s global graph plots energy consumption for liquids, coal, natural gas, renewables and nuclear energy against year; its vertical axis is in $10^{18}$ joules. It shows past use from 1990 and then projected use towards 2040. The projected lines describe what was considered likely when the graph was made, not measurements from the future. A rising line means more energy used from that resource; it does not, by itself, show whether that resource’s share of all energy use has risen.

The graph shows rising global demand and projects substantial continued use of fossil fuels. Population growth and technological and industrial development can increase demand; China’s energy use, for example, grew rapidly between 2000 and 2015. Fossil fuels’ concentrated energy and established use help explain why they may remain important despite environmental problems. But coal, oil and gas are non-renewable, so their use cannot rise indefinitely from finite supplies. Nor does a global graph reveal a particular country’s fuel mix without separate national data.

Evidence informs decisions but cannot make them

Scientists can identify emissions, contamination and other environmental effects. Deciding what to do with that evidence also involves political, social, ethical and economic judgements. Governments may consider the cost of a cleaner alternative, jobs and energy supply, the views of affected people, and whether today’s choices leave harm or scarce resources for future generations.

Imagine a council considering whether to extract shale gas and burn it as fuel. It could weigh the gas supply and possible employment against the carbon dioxide released when it is burned, environmental effects of extraction and local objections. Evidence helps the council judge likely consequences, but cannot alone decide how much weight to give each concern.

Environmental impacts

Burning fossil fuels releases carbon dioxide, contributing to global warming; sulfur-containing fuels can release sulfur dioxide, contributing to acid rain. Extraction can also damage land or water. Nuclear generation avoids fuel-combustion emissions during operation but creates radioactive waste and carries an accident risk. Renewables avoid some combustion impacts, yet installations, manufacturing or bio-fuel production can affect habitats, land or air quality.

Trends and decisions

Read a graph’s axes, units and dates; separate measured history from projections. Rising use of a resource does not necessarily mean a rising share of total use. Population and industrial development can increase demand, while finite supplies limit non-renewable resources.