The physical and human causes of climate change, the local and global effects, and the management strategies and their limitations.

What this key area is asking

The SQA wants you to separate the physical from the human causes of climate change, describe the effects at both local and global scales, and evaluate the strategies used to manage it, including their limitations. Higher marks depend on naming examples and reaching a judgement, not just listing.

Causes of climate change

Physical (natural) causes include changes in the Sun's energy output (sunspot cycles), major volcanic eruptions that throw ash and aerosols into the atmosphere and briefly cool the planet, slow changes in the Earth's orbit (Milankovitch cycles that drove past ice ages), and natural shifts in ocean currents such as El Nino. Human causes dominate recent warming through the enhanced greenhouse effect: burning fossil fuels for energy and transport, deforestation that removes carbon-absorbing trees, and agriculture that releases methane from cattle and rice. Atmospheric carbon dioxide has risen from about $280$ parts per million before industrialisation to over $420$ today.

Effects of climate change

The effects operate at two scales the SQA asks you to separate. Global effects include sea-level rise, ice loss and shifting biomes. Local effects include, in Scotland, milder wetter winters, more frequent flooding (Storm Desmond, 2015), and threats to ski tourism in the Cairngorms as snow cover declines.

Managing climate change

Strategies fall into two groups:

• Mitigation reduces emissions: switching to renewable energy (Scotland sourced around $97\%$ of its electricity demand from renewables in 2020), improving energy efficiency, carbon capture and storage, reforestation, and international agreements such as the 2015 Paris Agreement, which set a goal of keeping warming well below $2^{\circ}C$.
• Adaptation copes with unavoidable change: building sea defences (the Thames Barrier protects London), developing drought-resistant crops, improving water storage, and flood management.

Examples in context

Example 1. The Paris Agreement (2015). Nearly 200 countries agreed to limit warming to well below $2^{\circ}C$, aiming for $1.5^{\circ}C$, with each setting its own emissions pledge. As a management strategy it shows both strengths and limits: it created near-universal commitment and a review mechanism, but the pledges are voluntary and unenforceable, the United States temporarily withdrew (2017 to 2021), and the combined pledges still put the world on track for more than $2^{\circ}C$. It is the standard named example for evaluating international agreements.

Example 2. Scotland's renewable transition and the Maldives' vulnerability. Scotland shows mitigation in action, generating the equivalent of around $97\%$ of its electricity demand from renewables in 2020, mainly wind and hydro. The Maldives shows why action matters: with most land under $1\ m$ above sea level, rising seas threaten the entire nation, and it has invested in sea defences and even artificial higher-ground islands as adaptation. Together they contrast a wealthy country mitigating with a poor country forced to adapt, illustrating climate justice.

Try this

Q1. Explain the human causes of climate change. [4 marks]

• Cue. Burning fossil fuels releases carbon dioxide; deforestation removes trees that absorb carbon; farming releases methane; together these strengthen the enhanced greenhouse effect and trap more heat.

Q2. Discuss the limitations of strategies used to manage climate change. [4 marks]

• Cue. International agreements are voluntary and hard to enforce; renewable energy is costly and weather-dependent; carbon capture is unproven at scale; the poorest countries that suffer most can least afford to adapt.