Climate Change
AdvancedRising greenhouse gases (CO₂, methane) warm the planet, bringing extreme weather, sea-level rise and ecosystem shifts. For Hong Kong: more hot days, heavier rainstorms, more extreme typhoons. Responses split into mitigation (cut emissions) and adaptation (stronger infrastructure, warnings).
- Cause: rising greenhouse gases
- Impacts: extremes, sea-level rise; HK: hotter, wetter
- Response: mitigation + adaptation together
§Text Passage
1The main cause of climate change is human activity: burning vast quantities of coal, oil and other fossil fuels, together with large-scale deforestation, keeps raising the concentration of carbon dioxide, methane and other greenhouse gases. The enhanced greenhouse effect traps more heat inside the atmosphere, and the global average temperature has climbed over the long term, accelerating in recent decades. Remember the difference between weather and climate: one year's cold snap is a short-term weather event and cannot refute a decades-long warming trend.
2The impacts of warming are surfacing around the world: glaciers and ice sheets melt faster, seawater expands as it warms, and sea levels keep climbing, hitting low-lying island nations such as Tuvalu first, while heatwaves, downpours and fierce typhoons strike more often. Hong Kong feels the change directly: very hot days keep rising, threatening outdoor workers and the elderly; rain falls in sharper, heavier bursts, deepening the risk of flooding and landslides; and stronger typhoons bring greater storm-surge danger to low-lying coasts.
3The response must run on two tracks. Mitigation treats the root cause: develop renewable energy, improve energy efficiency, choose low-carbon transport such as public transit and electric vehicles, and plant forests that absorb carbon dioxide — cutting greenhouse-gas emissions at the source. Hong Kong has pledged carbon neutrality by 2050, meaning emissions balanced by absorption for net zero, a goal that demands long-term commitment from government and citizens alike.
4Adaptation copes with changes already underway: strengthen drainage and flood defences, build heat-resilient features such as shading and ventilation into buildings, and upgrade extreme-weather warning systems. Because climate change respects no borders, the Paris Agreement pledged to hold warming to within 2°C above pre-industrial levels, striving for 1.5°C, with progress reviewed regularly at the UN climate conferences. Even if emissions stopped today, the warming already underway would continue — so mitigation and adaptation are both indispensable.
1Summary 重點摘要
Rising greenhouse gases (CO₂, methane) warm the planet, bringing extreme weather, sea-level rise and ecosystem shifts. For Hong Kong: more hot days, heavier rainstorms, more extreme typhoons. Responses split into mitigation (cut emissions) and adaptation (stronger infrastructure, warnings).
2Vocabulary cards Vocabulary
The natural trapping of heat by atmospheric gases; excessive = global warming.
Cutting emissions — tackling the cause.
Adjusting lives and infrastructure to changes already underway.
Emissions = removals, net zero. Hong Kong targets this by 2050.
Gases such as CO₂ and methane that absorb and trap heat.
The long-term rise in global average temperature — the core of climate change.
Melting glaciers and expanding warmer water lift the seas.
Heatwaves, downpours and fierce typhoons — growing more frequent as the planet warms.
Weather is short-term and local; climate is the ~30-year average.
3Step by step Steps
- Causes recapThe main cause of climate change is human activity: burning vast quantities of coal, oil and other fossil fuels, together with large-scale deforestation, keeps raising the concentration of carbon dioxide, methane and other greenhouse gases. The enhanced greenhouse effect traps more and more heat inside the atmosphere, unable to escape to space. Global average temperature has therefore climbed over the long term, and in recent decades the rise has accelerated far beyond the pace of natural change.
- Global impactsThe impacts of warming are surfacing everywhere: rising temperatures melt glaciers and ice sheets faster, seawater expands as it warms, and sea levels keep climbing, hitting low-lying island nations such as Tuvalu and coastal cities first. Heatwaves, downpours and fierce typhoons strike more often, raising the risks of crop failure, water stress and ecological imbalance, while species vanish faster and food security faces a stern test.
- Hong Kong impactsClimate change is already visible in Hong Kong: very hot days and night-time temperatures keep rising, threatening the health of outdoor workers and the elderly; rain falls in sharper, heavier bursts, deepening the risk of urban flooding and landslides; typhoons are intensifying and storm surges menace low-lying coasts more than ever; and warmer, acidifying seas are stressing coral and marine ecosystems, with fisheries and biodiversity affected too.
- Mitigation (root)Mitigation treats the root cause: develop renewable energy, improve energy efficiency and save electricity, choose low-carbon transport such as public transit and electric vehicles, and plant forests that absorb carbon dioxide — cutting greenhouse-gas emissions at the source. Hong Kong has pledged carbon neutrality by 2050, meaning emissions balanced by absorption for net zero, a goal that demands long-term commitment from government and citizens alike.
- Adaptation (symptom)Adaptation copes with changes that have already happened: strengthen drainage and flood defences against downpours, build heat-resilient features such as shading and ventilation into design, upgrade extreme-weather warning systems, and extend coastal protection along the seafront. Mitigation treats the cause and adaptation eases the symptoms — they are not either-or: even if emissions stopped today, the warming already underway would continue, so both tracks must run in parallel.
- Global cooperationClimate change respects no borders, and no country can solve it alone, so global cooperation is essential. The Paris Agreement of 2015 pledged to hold the rise in global temperature to within 2°C above pre-industrial levels, striving for 1.5°C; each country submits its own emission pledges, and progress is reviewed regularly at the UN climate conferences (COP). Hong Kong's pledge of carbon neutrality before 2050 is its answer to this international framework.
4Diagrams Diagrams
5Worked example Example
'It was cold this winter — so much for global warming?'
- Weather = short-term, local; Climate = long-term (30 yr), global
- One cold snap is a weather event
- Check the trend: HK's annual mean temperature and hot days keep rising
- Conclusion: one cold day doesn't refute decades of warming — different scales
- Answer: No — distinguish weather from climate: weather is short-term and local, and one winter's cold snap is just a weather event; climate is the decades-long global average. Hong Kong's annual mean temperature and hot-day counts keep rising, and so does the global trend — long-term warming is unchanged. Refuting decades of warming with one cold day confuses two different levels — the argument fails.
6Common mistakes Mistakes
7Quick check Quick check
Q1Why is the greenhouse effect being 'enhanced'?
Q2One example each of mitigation and adaptation.
Q3What is Hong Kong's 2050 climate target?
Q4What is the goal of the Paris Agreement?
Q5Why does global warming raise sea levels?
8Recap Recap
- Cause: rising greenhouse gases
- Impacts: extremes, sea-level rise; HK: hotter, wetter
- Response: mitigation + adaptation together
- One cold day doesn't refute decades of warming — different concepts
- Hong Kong: more hot days, heavier rainstorms, stronger typhoons