Hydrosphere | Biomes | Animal Migration | Agriculture
Climate change affects every part of the Earth system—from rising sea levels to shifting biomes and human health. While we live ensconced in comfort—heated rooms in winter and air conditioning in summer, we must stay aware of how our actions impact the planet. Even small changes can escalate and cause larger problems, a process known as the “butterfly effect“.
In IB Geography exams, you must know real-life examples of these happenings. Here’s a breakdown of high-impact revision content.
P.S The exam content in these posts is stripped down to the bare minimum. Full notes are based directly on past IB exam questions (ie. ocean routes disruptions, biomes diversity), with detailed case studies (Australia’s wildfires) and at least three exam-ready points per topic—available here.
Impacts on the Hydrosphere
The hydrosphere includes freshwater, seawater, and ice. It’s one of the first systems impacted by climate change.
- Sea-level rise due to melting icecaps adding volumes into the oceans, as well as thermal expansion when warmer oceans expand
Sea levels are rising faster than before → current rate is 3–5.2mm/year (double since the 1990s) → 500,000 UK homes are at risk of flooding from rising seas and stronger storm surges - Destruction of alps, ski chalets
Biomes
- Mangrove forests are dying due to rising salinity from sea-level rise
- Ocean acidification → excess CO₂ forms carbonic acid → lowers ocean pH → threatens coral reefs
Animal Migration & Species Distribution
- Mosquitoes now appear in highland areas → higher disease risks (malaria, dengue)
- Species loss in rainforests → reduces biodiversity, weakens ecological balance
Impacts on Agriculture
Climate change affects what we grow, where we grow it, and how stable our food supply is.
- Warmer temperatures → longer growing seasons → 2 harvests instead of 1
- Wine grapes ripen faster → changes in grape chemistry → viticulture moves uphill to escape heat
Human Vulnerability to Climate Change
Something that’s oft-asked in exams, is wealth and vulnerability, ie. are wealthier people less vulnerable? Yes, in most cases. Here’s why:
- They can move away from high-risk zones or climate-proof their homes
- They are less reliant on climate-sensitive sectors like farming
In contrast, low-income communities often:
- Live in flood-prone areas
- Lack access to education, warnings, or infrastructure
Human Factors That Increase Climate Vulnerability
- Poverty → limits housing choices → families settle in risky areas
- Low education levels → limited awareness of risks or how to prepare/respond
- Poor government spending → lack of early warning systems and disaster-proof infrastructure
Read here for more on Feedback Loops
Read here for more on Greenhouse Gas & Enhanced Greenhouse Gas Effect
Read here for more on how Government and TNCs can mitigate impacts of climate change
Full Global Climate Revision Pack available