🙈 Australia’s Exported Emissions + 🌊 SA’s Marine Heatwave

Hi and welcome back to your climate data briefing.

After a short hiatus, while we rolled out some major upgrades at onlyfacts.io (more on that soon), the prodigal briefing returns! 👩‍🚀

To make it up to you and claw back lost time, this one’s a double banger, with two spotlight stories.

🙈 First, a new addition to OnlyFacts - Australia’s exported emissions. Key takeaway: they’re three times higher than what we emit at home.

🌊 Second, the marine heatwave driving South Australia’s algal bloom.

Let’s dive in.

🙈 Spotlight #1: Australia’s Exported Emissions

Exported emissions are the greenhouse gases released when other countries burn Australian fossil fuels.

Australia digs up coal and gas but burns little of it at home. Instead, it sells these resources overseas, where the pollution is released out of sight and beyond the reach of our national reporting.

By exporting fuels meant to be burned, Australia effectively exports emissions.

To grasp the scale of these, let’s start with the exports themselves. Each quarter, the Department of Industry, Science and Resources releases data on Australia’s energy exports.

Here’s a snapshot of coal and gas. (Metallurgical coal is used to make steel and thermal coal powers electricity).

We estimate the emissions using factors published by the Department of Climate Change, Energy, the Environment and Water.

The result is a chart that mirrors the export volumes but with a different Y-axis: million tonnes of carbon dioxide equivalent (Mt CO₂-e), instead of fuel.

Add it all up, and Australia exports around 300 Mt CO₂-e each quarter.

Compare that to Australia’s reported domestic emissions. Instead of quarterly exports, we’ll use a rolling 12-month view.

• In the year to December 2024, Australia’s domestic emissions totalled 435.8 Mt CO₂-e.
• Over the same period, the fossil fuels we exported generated an estimated 1,207.8 Mt CO₂-e when burned overseas.

The chart is a doozy.

🌊 Spotlight #2: SA’s Algal Bloom and Marine Heatwave

South Australia’s algal bloom has dominated headlines for weeks.

‘Bloom’ is a pretty word we usually associate with flowers. Here, it means the rapid growth of microscopic algae. A harmful algal bloom (HAB) is the term for when toxic algae multiply out of control.

For surfers and swimmers, it has caused rashes, eye irritations and respiratory issues like wheezing. For marine life that can’t escape to shore, the bloom has been deadly.

Since February, the iNaturalist platform has recorded 18,379 marine deaths - undoubtedly an underestimate, given it captures only what citizen scientists have seen and reported.

The project (created by Brad Martin, a PhD candidate at Flinders University and Project Manager at OzFish Australia) collates all the platform’s crowdsourced observations of dead fish and other marine animals from February 2025. Here are the locations.

The South Australian government said three key events are behind the algal bloom:

1. 2022: floods flushed organic matter through the Murray-Darling Basin and out to sea.
2. Summer 2022/23: a cold-water upwelling lifted it to the surface.
3. September 2024 - present: a marine heatwave has created ideal conditions for the algae to … bloom.

Let’s look at the average sea surface temperature off SA.

The chart below shows the yearly temperature anomaly since 1900. That is, how each year’s sea surface temperature compares to the long-term average.

In 2024, sea surface temperatures off South Australia were more than 0.5°C above the average.

Here’s the monthly temperature anomaly through to June 2025. Note the consistently high temperatures above 0.5°C in the last seven months.

Blurbs

Worth Your Time

Abundance Down Under

How to fix Australia’s broken national environment laws. They promised ecologically sustainable development but do ‘little more than record the degradation of the natural world one project at a time.’ Renewable project approvals have blown out to 831 days. A 2021 review that still languishes unlegislated, called for a regional, rules-based system with clear standards and an end to the ‘raft of carveouts’. The benefits would flow beyond clean energy, to transmission infrastructure, critical minerals mining, transport and housing. (Ken Henry at the National Press Club, 17 July). 

Beyond Opposition

Climate leaders wrestle with a movement ‘built to stop bad stuff, not to build good stuff.’ When the crisis is seen only as an emissions problem, efforts skew towards opposing fossil fuels, rather than championing green solutions. EV incentives, clean exports, and transition research for poorer countries all lack champions. Project approval reforms that are tech-neutral could be more politically resilient while quietly favouring clean energy. The episode opens with a grim health check on US energy policy. If you’re short on time or patience, jump to the 35-minute mark. (The Ezra Klein Show/New York Times, 25 July).

New Technologies, Old Distortions

Highlights from AEMO’s Quarterly Energy Dynamics report. Big batteries were once expected to be grid shock absorbers, charging when power is plentiful and cheap, discharging when demand is high. Instead, they were the main driver for wild price spikes in the National Electricity Market (NEM) last quarter. On three cold evenings (11, 12, and 26 June), aggressive bidding by batteries pushed spot prices above $10,000/MWh. Those spikes alone added roughly $32 to the quarter’s average price of $140/MWh (Renew Economy, 31 July).

Headlines

What Happened This Week

Australia

Labor announced it will supersize its renewables subsidy scheme by 25% (The Australian Financial Review, 28 July)

The mining industry dropped references to ESG in its new reporting code draft (The Australian Financial Review, 28 July)

A court overturned on climate grounds a massive Hunter Valley coal mine approval (The Sydney Morning Herald, 25 July)

Fortescue axed two green hydrogen projects in Queensland and Arizona citing ‘lack of certainty’ (The Guardian, 25 July)

In the week prior, four in five Tuvaluans entered a ballot to move to Australia under a treaty that formalises climate‑driven migration (Sydney Morning Herald, 19 July)

The World 

Climate think tank Ember calculated the world is far off its goal to triple renewables (Bloomberg, 31 July)

The International Court of Justice found countries have an obligation to cut greenhouse gas emissions (Financial Times, 24 July)

A study linked price shocks in staple foods like potatoes and rice to extreme weather events around the world (The Wall Street Journal, 21 July)

Final Thought

'Ecology is actually mostly just statistics with some plants and animals in the mix.'
— Jonathan Tonkin

That's your climate data briefing. We'll see you next week … I promise!

💛 Juliette and the OnlyFacts team