What causes climate change?

Our journey to net zero – part 4

Climate change is driven by several factors, primarily resulting from human activities that release carbon dioxide and other gases into the atmosphere. The increase in global greenhouse gas emissions is closely linked to economic and population growth, which drives higher energy consumption, more industrial activity and changes in land use.

What are the key contributors?

1. Energy production and demand
   The global energy sector is heavily reliant on fossil fuels – mainly coal, oil and natural gas – which contributes significantly to global CO₂ emissions. The energy used for heating, cooling, lighting and operating appliances in buildings also largely comes from fossil fuels, particularly in regions without significant renewable energy infrastructure.
2. Transportation
   Vehicles powered by petrol and diesel, including cars, trucks, planes and ships, emit significant amounts of CO₂. This sector is one of the fastest-growing sources of greenhouse gases due to the increasing demand for personal travel and commercial transport.
3. Industrial processes
   Manufacturing industries emit a wide range of greenhouse gases (GHG), particularly when they involve energy-intensive processes, such as those needed to produce cement, steel and/or chemicals. Various industrial applications also require the use of synthetic gases, including hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulphur hexafluoride (SF6), which have a much higher global warming potential than CO₂.
4. Agriculture
   Besides methane and nitrous oxide, agriculture also contributes to CO₂ emissions with fossil fuels in farming equipment, the production of fertilisers and the conversion of natural ecosystems into agricultural land, which can release carbon stored in soils and vegetation.
5. Deforestation
   Trees absorb CO₂ during photosynthesis. When forests are cut down or burned, this carbon sink is lost, and the carbon stored in trees is released back into the atmosphere, further contributing to climate change. Deforestation also disrupts local climates and rainfall patterns.
6. Urbanisation and change of land use
   Changes in land use can lead to increased heat absorption by urban structures, contributing to local temperature rises, known as the ‘urban heat island’ effect. This can also affect local weather patterns and increase energy demand for cooling, further contributing to greenhouse gas emissions.
7. Waste management
   Landfills are significant sources of methane emissions as organic waste decomposes anaerobically. Inadequate waste management and treatment can lead to increased greenhouse gas emissions.

How are emissions categorised?

In the context of reporting and climate policy, greenhouse gas emissions are categorised into three scopes by the Greenhouse Gas Protocol. These widely-used international standards are key for setting science-based targets to reduce our carbon footprint.

• Scope 1 – These are direct emissions from company-owned or -run vehicles and facilities, including boilers, furnaces, vehicles, etc.
• Scope 2 – These are indirect emissions from purchased energy, such as electricity used to power lights, computers, heating, air conditioning, refrigeration, etc.
• Scope 3 – These are all other indirect value chain emissions, e.g. purchased goods and services, transportation and distribution, product materials, employee commute, business travel, use and waste of products, etc.

What is net zero?

Achieving net zero means reducing greenhouse gas emissions across all scopes by at least 90%. The emissions released into the atmosphere cannot be balanced by an equivalent amount being removed or offset elsewhere (e.g. by planting a tree or investing in carbon capture technologies), as is the case when a company product, service or event is carbon neutral.

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