On 20 March I spoke, together with Adam Bandt MP, at a forum in Melbourne on Global warming, Tony Abbott and the need for climate action.
The second half of my presentation was on how to turn the tide, looking at the "middle third" in recent polling and Tony Abbott's and his government's vulnerability on climate, and what they are desperate to not talk about:
- More and more intense extreme weather events (exemplified by their silence on the spring 2013 fires, and record January 2014 heat);
- A public conversation that "connects the dots" between extreme events and climate change, and which gives immediacy to the perception of climate impacts;
- Constructing a climate narrative about human climate impacts, rather than electricity prices and taxes;
- Public focus on the responsibility of political leaders to "protect the people" from climate change; and
- Close attention being paid to the efficacy of their "direct action" climate plan.
- People in Australia and not distant places;
- Now and not just the distant future;
- How family and friends will live in a hotter and more extreme world;
- How it will affect where we live and how we work; and
- Health and well-being, about increasing food and water insecurity, and the lives that children and grandchildren will face.
This post is about the first part of my presentation, on connecting climate extremes that are being experienced today to an understanding of what climate change will mean for people in the future.
A new climate regime
One starting point is to make it clear that we are moving to a whole new climate that will be a new experience to people wherever in the world they live. Carbon dioxide levels – the principal determinant of changing temperatures – are higher than at any time since modern human evolved, and likely higher than for the last 15 to 20 million years, so we are creating a new climate regime that humans have never experienced.
Climate change manifests not as a slow, imperceptible and smooth change, but as a series of extreme events that become increasingly frequent till they become the new norm. So these extreme events – record temperatures, longer and more intense heat waves, changing rainfall and drought patterns – are all a preview of what life will be like every day in a few decades time.
In January, Melbourne set two new extreme heat records:
- four consecutive days of maximums over 41°C;
- three days of where the average, 24-hour temperature was over 35°C (basically in the range of 28C-44°C).
|Courtesy: Prof. Tony McMichael|
And a new Climate Council report finds that over last 30 years, Melbourne heat-waves are occurring 17 days earlier, have become 1.5°C hotter, and the maximum temperature of the hottest day is 2°C higher, compared to 1950-1980.
Extreme heat affects workplace productivity. As the next chart shows, for medium-exertion work, when the temperature increases from 30°C to 34°C (at 20% humidity), productivity halves. By the time the temperature is around 40°C, productivity approaches zero.
|Courtesy: Prof. Tony McMichael|
Points of departure
A graphic way of demonstrating this is using resources from a paper published in October last year, "The projected timing of climate departure from recent variability".
The associated website includes data for many locations around the globe. Below is one projection for Melbourne. The research tracked average temperatures for each location from 1850 to 2005 (blue line) and established this historical temperature band (grey area). Then climate models for two emissions scenarios (RCP8.5 which is the high "business-as-usual" emissions scenario the world is current tracking on, in red; and a lower scenario, in yellow) were run to ask the following question: for each scenario, what is the year in which temperatures from that point on will all be higher than the current band. For Melbourne the answer for one climate model (Institut Pierre Simon Laplace Earth System Model CM5A-M) is 2034 (high emissions) and 2047 (medium emissions):
|Melbourne: point of departure from current climate|
|Point of departure from 1850-2005 climate |
for major Australia cities for RCP8.5 and RCP4.5
And here is the Sydney result for the Institut Pierre Simon Laplace Earth System Model CM5A model:
|Sydney: point of departure from current climate|
And it is not just about air temperatures. Waters around Australia had hottest sea surface temperatures on record in February 2013. In the last four years, we have experienced unprecedented and out-of-season bush fires, a record two years of rain, repeated “1-in-a-100-year” floods, as well as record heat.
And, of course, it's not just Australia. One well-studied extreme event is the European/French heatwave of 2003, which killed 70,000 people, resulted in a 30 per cent drop in plant growth and caused $12 billion of crop losses, adding half a billion tonnes of carbon to the atmosphere. As the next image shows, in 35 years time, the 2003 extreme will be the average climate for that region:
We know quite a bit about a 2°C world from climate history research. Three million years ago in the mid-Pliocene, when greenhouse gas levels similar to today and sufficient for 2°C of warming, sea levels were 20 metres or more higher than today. Yet with a 5-metre rise, Miami would disappear and Central London, Bangkok, Bombay and Shanghai would lose most of their area. Rich food-growing deltas such as Nile, Mekong and Brahmaputra inundated.
At 2°C warmer, every year in Australia would likely be hotter than the hottest year up to 2005; there would up to a doubling of days over 35°C, and roughly a doubling in extreme fire days. The barrier reef would be lost, Kakadu salinated, Murray Darling water flows down by about a quarter, and seas would be on the way to rising several metres in a nation where 85% of the population lives within 50 kms of the coast. In Australia, more than $200 billion worth of coastal assets and 700,000 properties are at risk from a sea level rise of just 1.1 metre.
What more can we do to connect the dots between today's extreme experiences and tomorrow's world?