Understanding Climate Change: AQA GCSE Geography

Recent Extreme Weather Examples

The UK has been smashed by some absolutely mental weather in recent years. Kent hit a scorching 38.5°C in 2008, whilst the Beast from the East in March 2018 brought Arctic conditions that had everyone panic-buying bread and milk.

Things got even weirder in 2019 when February temperatures reached 21.2°C at Kew Gardens (basically T-shirt weather in winter!), and Lincolnshire got hammered with 7.5 times its monthly rainfall in just three days during June.

Global warming is pumping more energy into our atmosphere, creating more intense storms and unpredictable weather patterns. The most mental bit? Six of the ten most active hurricane years in the North Atlantic since 1950 have happened since the mid-1990s.

Quick Fact: Storm Ellen and Storm Frances hit the UK within just three days of each other in 2020 - the most notable storms in 50 years!

The jet streams that normally push weather systems across the UK are getting "stuck" more often. When this happens, we end up with the same weather for ages - either boiling hot spells or endless rain. Scientists reckon this is happening because the Arctic is warming faster than other regions, which slows down the jet stream and leaves us trapped under the same weather pattern for longer.

Climate Change Through Time

Your planet's been on a wild temperature ride for millions of years, and understanding this helps explain why today's climate change is so significant. Over the past 5.5 million years, Earth's temperature has generally been cooling down, but the ups and downs have become more dramatic.

The Quaternary period (the last 2 million years) shows a clear pattern of alternating cold periods called glacials and warm periods called interglacials. These swings happen roughly every 100,000 years, and here's the kicker - today's temperature is higher than almost all of the last 400,000 years.

Since 1880, things have really kicked off. Global temperature has risen by 0.85°C compared to the 1901-2000 average, with the steepest rise happening since the 1980s.

Reality Check: That 0.85°C might not sound like much, but it's absolutely massive on a global scale - enough to trigger the extreme weather we're seeing today.

The graphs show that whilst natural climate swings used to take thousands of years, we're now seeing rapid changes within decades. This speed of change is what makes current climate change so different from anything our planet has experienced before.

Finding Evidence of Past Climates

Scientists are basically climate detectives, digging up clues about Earth's weather history from some pretty clever places. Sediment cores from lake bottoms contain pollen that reveals what plants were growing thousands of years ago - tropical pollen means the climate was much warmer back then.

Ice cores are like nature's time capsules. Scientists drill deep into ancient ice and extract air bubbles that contain CO₂ from thousands of years ago. Low CO₂ levels usually mean the climate was colder, whilst high levels suggest warmer periods.

Dendrochronology (tree ring dating) shows annual growth patterns in trees. Thick rings mean good growing conditions with warm, wet weather, whilst thin rings suggest harsh years with cold or dry conditions.

Cool Fact: Fossils of animals that now live in warm climates tell us those areas used to be much hotter - imagine finding crocodile fossils in Scotland!

Milankovitch cycles explain the natural climate swings over thousands of years. Earth's orbit changes shape every 100,000 years, its tilt shifts every 41,000 years, and it wobbles like a spinning top every 26,000 years. When these cycles align, they can trigger ice ages or super-warm periods.

Sunspot cycles also affect our climate. The sun goes through 11-year cycles from minimum to maximum sunspot activity, with maximum periods creating solar flares that pump out more heat.

Volcanic Climate Disruption

Volcanic activity can proper mess with global climate by chucking massive amounts of debris into the atmosphere. This stuff blocks sunlight and creates sulphuric acid droplets that reflect heat away from Earth, causing temperatures to plummet.

The 1815 eruption of Mt Tambora in Indonesia shows just how mental volcanic impacts can be. Global temperatures dropped by 0.4°C to 0.7°C, which might not sound like much but caused widespread crop failures and famines that killed around 200,000 people.

Mind-Blowing Fact: One massive volcanic eruption can affect global weather patterns for years, proving how interconnected our planet's climate system really is.

Understanding these natural causes of climate change helps scientists work out what's normal variation and what's being caused by human activities. Whilst volcanoes and solar cycles have always influenced our climate, the current rapid warming is happening way too fast to be explained by natural causes alone.