The United Nation's top official on climate change, Christiana Figueres. Photo: Brendan Esposito
The world remains on course to exceed dangerous
temperature increases even if nations carry out pledges they make
at next month's global climate summit in Paris, the United Nations says.
An
assessment by the UN of 146 national goals and those of the European
Union covering about 86 per cent of greenhouse gas emissions found they
would cut average per capita pollution by as much as 8 per cent by 2025
and 9 per cent by 2030 compared with the current trajectory.
So-called
Intended Nationally Determined Contributions (INDCs) represent a big
step forward from the 2009 Copenhagen summit but still fall short of
keeping temperatures to within two-degrees warming on pre-industrial
levels that scientists say would trigger dangerous climate change.
"The
INDCs have the capability of limiting the forecast temperature rise to
around 2.7 degrees by 2100, by no means enough, but a lot lower than the
estimated four, five, or more degrees of warming projected by many
prior to the [pledges]," Christiana Figueres, Executive Secretary of the
UN Framework Convention on Climate Change, said.
Just weeks to go before the summit, global heat records continue to tumble. Vrendendal in South Africa recorded 48.4 degrees on Tuesday, the hottest recorded temperature in October anywhere.2015 remains odds on to smash annual records after September was the most unusually warm month in 1629 monthly records kept by US agencies.
This
month is also likely to be Australia's hottest October as the powerful
El Nino adds to be background warming from climate change.
Australia
has promised to cut 2005-level emissions 26-28 per cent by 2030 - a
target that while relatively ambitious on a per capita basis would still
leave the country with the highest pollution per person among rich
nations.
Prime Minister Malcolm Turnbull is expected to attend the
opening day of the Paris conference, joining world leaders expected to
call for bolder action to curb greenhouse gas emissions.
A climate
meeting of negotiators in Bonn, Germany earlier this month made little
progress, with the draft text of the Paris agreement swelling out to 55
pages.
The final agreement is expected to contain few specific
numbers, in part to enable US President Barack Obama to impose
regulatory measures to curb emissions in the world's second largest
polluting economy without the need to seek approval in the hostile
Republican-dominated Senate.
Key differences, though remain
between rich and developing nations. The latter want to see a firm
commitment to increase the combined public and private financial aid
from a goal of $US100 billion ($141 billion) a year beyond 2020, while
the former want greater transparency and accountability for national
emissions.
A worst-case scenario could a very minimalist agreement "with a bow-tie put around the INDCs", one source said.
The
negotiations at Paris are also likely to focus on the durability of any
pact and whether nations will be obligated to lift their commitments at
each future review, possibly set at five-year intervals.
With the
Paris pledges falling short of the two-degree target, many observers
are arguing the event will likely be the start of a new process to
reduce emissions rather than the end of the road.
Environment
Minister Greg Hunt is expected to attend the first week of the
conference with Foreign Minister Julie Bishop likely to attend at least
three days in the second week.
Early heat in Victoria helped fan bushfires in October. AAP Image/Tracey Nearm
This has been Australia’s hottest October on record. Barring an
(extremely unlikely) cold snap, it will also be the hottest October for
Victoria, and for Melbourne. And the record-breaking temperatures are at
least six times more likely thanks to human-induced global warming.
But hold up, you say, October isn’t over yet! That’s true, but going by the current forecast from the Bureau of Meteorology we can see that new record high October average maximum temperatures are virtually certain.
In fact, the maximum temperature on Saturday would need to be below
freezing across Victoria for the record not to be set, and there is no
physically plausible scenario that could lead to that happening. Maybe
if an asteroid landed in Victoria on Saturday (Halloween) and threw up enough dust to block out the sun? But that is very, very unlikely!
The very hot spell that hit Australia in early October. Note parts of south east Australia experienced temperatures 8-10C above average. Australian Bureau of Meteorology
New record highs have been set for monthly and seasonal average temperatures across Australia at 12 times the rate of new record lows. Global warming is the cause.
To understand the role of human-caused global warming in the new records we compare simulations of the Earth’s climate from nine different models from around the world.
We only select climate models that do a good job of simulating the natural year-to-year variability of Australian temperatures. We then compare simulations for the current climate (with human influence) and for the climate without human influence.
This approach has been used already to show the important role of global warming in record high Australian temperatures in 2013.
Using this method we can figure out the chances of breaking a record even before it happens. The previous hottest October in Australia was in 2014 with a temperature of 32.9°C. Our analysis shows an increase by at least a factor of six in the chances of setting the new October record maximum temperature for Australia due to global warming.
What about El Niño?
But we also have to factor in El Niño. As noted by the Bureau of Meteorology, such hot and dry spells are typical for the strong El Niño that is currently occurring in the Pacific Ocean.
To do this we use a huge set of data from a citizen science project called Weather@home ANZ. Weather@home allows you to donate your computer’s processing power to simulate Australia’s climate with and without human-caused climate change, and including El Niño.
This modelling approach, undertaken in partnership with the University of Oxford, has been used to assess the role of climate change in extreme weather and climate events in Australia in 2013 and 2014 and for typical El Niño conditions, such as this October.
We have more than 4,000 independent simulations of Australian weather and climate in October under El Niño conditions in the present world, and more than 8,000 simulations for El Niño conditions in a pre-industrial world with no human influences on climate.
These simulations allow us to assess the chances of breaking the existing records for October mean maximum temperature for the whole of Australia, for Victoria and for Melbourne under the current El Niño conditions.
For example, the figure below shows the simulated frequency of different October mean maximum temperatures for Melbourne with and without global warming.
The chances of higher October mean maximum
temperature in Melbourne during an El Niño year are much greater due to
global warming. The current record is shown by the vertical line.
The current record high mean maximum temperature of 23.7°C was set in October 1940. The chances of breaking the current record are much greater for the current climate, including the influence of global warming, than they would have been with no global warming.
In fact, human-caused climate change has very likely increased the chances of setting the new record for Melbourne by at least six times, even under El Niño conditions.
For the whole state of Victoria, global warming has increased the chances of breaking the existing record by at least six times, while for Australia under El Niño conditions, global warming has increased the chances by at least ten times. This is more than the increase found using the other climate models mentioned above, because now we have also taken into account the influence of El Niño.
Climate change due to human activity has dramatically increased the chances of setting new record temperatures in Melbourne, Victoria and Australia in October this year.
Of course, we have to wait another couple of days to see if our predictions hold true. But we are pretty confident they will.
