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Key Points
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As public awareness of climate change continues to grow, much of the attention understandably centres on visible signs: melting glaciers, scorched bushland, and record-breaking heatwaves.
Yet behind these headlines lie lesser-known but critical scientific truths.
They highlight the full scope of climate disruption and suggest cascading consequences for ecosystems, economies, and communities alike.
Here are several surprisingly overlooked facts that shed new light on climate change, global warming, and the greenhouse gases driving them.
Oceans: The Silent Heat Sink
While many people associate climate change mainly with rising temperatures in the air, the reality is that most of the planet’s excess heat doesn’t stay in the atmosphere — it heads straight into the sea.
According to the Intergovernmental Panel on Climate Change (IPCC), nearly 90 per cent of the excess heat generated over the past five decades has been absorbed by the world’s oceans. 1
That heat, stored deep below the surface, is powering more intense cyclones, rising sea levels, and widespread coral bleaching.
Because oceans warm more slowly than air, they’ve helped to mask the true intensity of global warming, all while driving subtle but significant shifts in Earth’s climate systems.
Methane: A Fast-Acting Culprit
While carbon dioxide takes centre stage in discussions about emissions, methane (CH₄) — mostly released through livestock, landfills, and gas extraction — is an even more potent, though short-lived, greenhouse gas.
Over a 20-year period, it’s capable of trapping up to 80 times more heat than carbon dioxide, according to Australia’s CSIRO and the U.S. Environmental Protection Agency. 2
Though methane only lingers in the atmosphere for about a decade, its climate impact during that time is enormous.
Reducing methane presents a rare opportunity: a fast, high-impact strategy to limit near-term warming while addressing manageable sources.
Thawing Permafrost: A Dangerous Feedback Loop
Hidden beneath far northern soils lies a vast stretch of permanently frozen ground known as permafrost.
These frozen layers, rich in ancient carbon, are beginning to thaw as temperatures rise.
That thawing releases carbon dioxide and methane into the atmosphere, creating a dangerous feedback loop that could further accelerate planetary warming. 3
The Arctic permafrost region holds roughly twice as much carbon as the entire atmosphere.
Some areas are breaking down much sooner than researchers previously believed.
The unpredictable nature of these emissions represents one of the greatest unknowns in global climate forecasting.
Coral Reefs: Sentinels of Sea Change
Nowhere is the impact of warming oceans felt more acutely than on the coral reefs that surround Australia and other tropical coastlines.
Often called the “rainforests of the sea”, coral reefs support over a quarter of all marine species. 4
What’s less commonly known is how sensitive they are to temperature changes.
Even a small rise in sea temperature can cause corals to expel their symbiotic algae, resulting in bleaching events that strip reefs of their colour and vitality.
The world has already lost around half its coral reefs over the past 30 years, and scientists warn that without immediate action, much of what remains may vanish in the decades to come.
CO₂ Levels Not Seen in Two Million Years
Before the industrial era, global CO₂ concentrations hovered around 280 parts per million (ppm).
Today, that number has surged past 420 ppm, reaching levels not seen for at least two million years, based on geological evidence. 5
This spike isn’t part of a natural cycle — it’s the direct result of burning fossil fuels and clearing forests on a massive scale.
The speed at which this change is occurring is unlike anything Earth has experienced in recent history.
That rapid pace leaves ecosystems and human systems with precious little time to adjust.
Ocean Acidification: The Invisible Threat
Carbon dioxide doesn’t just warm the atmosphere.
Roughly a quarter of human-generated CO₂ is absorbed by the ocean, causing seawater to become more acidic. 6
This process — known as ocean acidification — is making life difficult for shell-building creatures like oysters, mussels, and tiny plankton that anchor the marine food web.
Lower pH levels also pose a risk to Australia’s aquaculture industry and Indigenous communities who depend on healthy coastal ecosystems.
While ocean absorption of CO₂ reduces atmospheric concentrations, it comes with a hidden cost: the slow deterioration of life beneath the waves.
The Verdict: A Changing Earth with Hidden Complexity
All of these often-overlooked facts point towards a powerful realisation: climate change is not just about rising temperatures.
It represents a far-reaching transformation of Earth's physical, chemical, and biological systems.
From melting permafrost to acidifying oceans and vanishing coral reefs, ecosystems are reacting in ways that are often subtle — and sometimes irreversible.
Understanding these lesser-seen dimensions is essential not only for scientists, but for everyday Australians too.
They inform how we adapt, how we invest in the future, and how we hold governments and corporations to account.
Because more than ever, the climate fight isn’t just urgent — it’s deeply personal.
Footnotes
- Oceans Absorb Global Heat — NOAA Climate.gov – How much of global warming is absorbed by the ocean?
- Methane Potency — Environmental Defense Fund – Methane: The Other Important Greenhouse Gas
- Permafrost Carbon Risk — NASA Earth Observatory – Permafrost and the Global Climate System
- Coral Reefs and Biodiversity — GCRMN – Status of Coral Reefs of the World: 2020
- CO₂ at Record Levels — NOAA – Carbon dioxide now more than 50% higher than pre-industrial levels
- Ocean Acidification in Australia — Australian Government – What is ocean acidification?
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