Scientists have discovered the presence of chemical pollutants in some of the ocean's deepest trenches, previously thought to be nearly untouched by human influence.

Sydney and much of NSW will take a rare break from this summer's extraordinary run of warmth, with a day or two of milder conditions before temperatures and fire risks start to climb again.

• COMMENT

Consumers are voters and they won't forget who is to blame if there's a meltdown in our nation's energy supplies.

Meteorologists were predicting NSW would set a state-wide record for February warmth during the current heatwave but few would have tipped the mark would be broken two days in a row.

A small town in central western NSW has been "all but wiped out" in a bushfire that ravaged the area, a resident claims, as firefighters continue to battle more that 80 blazes burning across the state.

Former Republican congressman Bob Inglis knows something about the cost of climate change. It included his job.

NSW is facing the "worst possible fire conditions" in its history with a "catastrophic" warning in place across large slabs of the state after a heatwave smashed temperature records on Saturday. 

• Live

Human activity heats up cities to such an extent that on the weekends when we're having a sleep-in, the centre of town is measurably cooler.

Rural Fire Service Commissioner Shane Fitzsimmons said the situation was as "bad as it gets".

Power to the country's biggest aluminium smelter, Tomago Aluminium, will be cut back on Saturday for the second day running as an unprecedented heatwave gripping NSW pushes power reserves to the limit.

Ugly scenes have unfolded at Queensland's Sea World theme park where animal activists ambushed a dolphin show - and then clashed with angry onlookers.

Wayne "Bronco" Lunn has endured many summers in the shearing business in north-western NSW over four decades but he's never seen one like this year's.

• ANALYSIS

Pointing our solar panels in the wrong direction is only one quirk in our strained energy system.

Incessant barking, constant shedding, murderously quick on their feet... Maremma dogs aren't easy, but for chicken farming? They're worth it.

Hundreds more whales have swam into shore at the site of an earlier stranding at Farewell Spit as the tide came in, sending volunteers scrambling.

As Sydney endures another heatwave, sweltering through what is likely to be its hottest summer on record, there are places where the heat is not just extreme but excruciating.

Authorities are pleading for public help to avoid blackouts and limit fire risks as a record-breaking heatwave sets in across eastern Australia.

Sydney has sweltered through another record-breaking day in summer of peak heat, with hospitals remaining on alert, power cuts hitting businesses and sports competitions scrambling to cancel weekend events.

HCF has become the first Australian health insurer to commit to divesting from fossil fuels, saying it cannot keep funding activities that could threaten its members' health.

Snow is expected to fall in Tasmania this weekend while most of the nation swelters in a heatwave.

The Turnbull government's recent embrace of coal-fired power shows it has "abandoned all pretense of taking global warming seriously", prompting Clive Hamilton to resign as a member of the Climate Change Authority.

Sydney and the rest of NSW are expected to bake from Friday to Sunday, with authorities expecting a spike in electricity use as fans and air conditioners whir into action across the state.

NSW faces biggest test of the summer, with soaring temperatures set to bring "catastrophic" fire conditions to some areas.

China has ordered an investigation after online images showed officials holding a lavish banquet of meat from the endangered pangolin, the most trafficked mammal on earth.

NSW faces potential power shortages during the coming heatwave, prompting the electricity market operator to demand additional supply.

Newly discovered gecko looks like a fish until you grab it, and then it looks like a naked chicken breast.

The most extensive heatwave of the summer is building over inland Australia, setting up Sydney and much of the state for record-tilting heat over the coming weekend.