IPCC issues dire climate warning, says coal must go to save Great Barrier Reef   



ABC News
October 9 2018


Australia and the rest of the world must virtually eliminate the use of coal for electricity within 22 years if there is to be a chance to save even some of the Great Barrier Reef, the world's most authoritative climate science body has warned.   
Key points:

    Greenhouse gas pollution must reach zero by about 2050 to stop global warming at 1.5C, a report by the UN climate body warns
    At 1.5C coral reefs are expected to decline by a further 70 to 90 per cent, the report says
    Experts say coal power needs to drop to between 0 and 2 per cent of existing usage

In a report authored by more than 90 scientists, and pulling together thousands of pieces of climate research, the UN's Intergovernmental Panel on Climate Change (IPCC) said global emissions of greenhouse gas pollution must reach zero by about 2050 in order to stop global warming at 1.5 degrees Celsius.

At current rates, they said 1.5C would be breached as early as 2040, and 2C would be breached in the 2060s.

If that happens, temperatures over many land regions would increase by double that amount. And at 2C of warming, the authors warn the world would risk hitting "tipping points", setting a course towards uncontrollable temperatures.

With the world already 1C warmer than pre-industrial times, experts said this report, released by the IPCC in Incheon, Korea, was likely our final warning before it becomes impossible to keep warming at 1.5C.

"To limit temperature change to 1.5 degrees we have to strongly reduce carbon dioxide emissions," said report contributor Professor Mark Howden from ANU. "They have to decline about 45 per cent by 2030 and they have to reach zero by 2050.

"We're not on track. We're currently heading for about 3 degrees to 4 degrees of warming by 2100."
1.5C vs 2C: What's the difference?   

Coral reefs would be a particular casualty. They are expected to decline by a further 70 to 90 per cent even under 1.5C, but that rises to more than 99 per cent reef loss as temperature rises hit 2C.

In Australia, that means the vast majority of the Great Barrier Reef will undergo significant upheaval or collapse.   

Combined with increased ocean acidification due to higher carbon dioxide concentrations, this is expected to heavily affect fish stocks and diversity.

Meanwhile on land, a rise of 2C would mean three times as much of the earth's terrestrial ecosystems would undergo transformations, compared to a rise of 1.5C, significantly increasing species extinctions.
Ice melts will become more frequent and intense
We'll see an ice-free Arctic every 10 years under 2 degrees of warming.


Then there are the rising waters. Modern humans have never seen an ice-free Arctic, but at 2C that would happen once a decade, compared to once a century at 1.5C.

A 2C rise would also mean an extra 10 centimetres of average sea-level rise by the end of the century, affecting an extra 10 million people.

And while some are inundated, a 2C rise would also double the number of people experiencing water scarcity.   

We would be hit with more extreme hot weather events in every part of the world: more floods in most, and more drought in some.

Those extreme events would be "far worse" as temperature increases go beyond 1.5C, according to Will Steffen from ANU's Climate Change Institute.

"Loss of the Amazon forests, melting of the permafrost, loss of ice in West Antarctic and Greenland, they are much riskier at 2 degrees than they are at 1.5," Professor Steffen said.

"They could lead to a tipping cascade where the system will get hotter and hotter even if we bring our emissions down."
Coal use needs to drop to '0 to 2 per cent': expert

In 2015, almost every country agreed to stop global warming at "well below" 2C under the Paris Agreement, and to try to limit it to just 1.5C.

But 1.5C is a global average, which is dampened by ocean temperatures and doesn't represent regional extremes, according to report contributor Jatin Kala from Murdoch University.

"Even some world leaders seem to think that 1.5 degrees is a small number. 'Why do we care?'" Dr Kala said.

"Warming over the land is at a higher level of magnitude. We care because when the global average is 1.5 degrees warmer, that means that several regions of the world are warming at much higher magnitudes — they'll be a lot warmer than 1.5."
Coal fired power needs to be phased out, scientists say
Coal power needs to drop to below 2 per cent of current usage to keep the temperature rise to 1.5 degrees.


To limit warming to 1.5C, there needed to be "deep changes in all aspects of society", according to Professor Howden.

"It does actually require major transformations in many aspects of society and to do those transitions, the next 10 years is critical," he said.

"Electricity will have to be supplied by renewables on a global basis by the tune of about 70 to 85 per cent of electricity supply.

You don't need a science degree to get the idea that burning stored energy from the Sun that took millions of years to lay down - e.g. Coal ... in only a couple of centuries is going to throw things out of balance.

It ain't rocket science. 

Seems that the graph you posted is on a positive trend and rising?

When it goes negative ... give us a shout eh?

BTW - Did you notice the annotation? It reads in part "Global (70S to 80N) Mean TLT Anomaly plotted as a function of time. "

Not even Global temperature but a subset. Unless of course global now means something less. Who knows with climate science?

Captain Nemo wrote on Oct 10^th, 2018 at 3:30pm:



That's only according to the ice core data which has its own problems. CO2 LAGS temperature, CO2 in the firn.

You do understand what happens with data when it is compressed to fit a tight page format? The data is lost.

800,000 years of data compression?

Also you ignore the plant stomata data which shows more variability in CO2 concentrations than ice core data.