Climate Change

Climate Change Anthropology

The risk that carbon based climate change poses to modern society should not be overlooked. Small changes in climate have played a role in the collapse of past societies. The collapse of the Nordic community on Greenland during the 15th century has been attributed to a decline in local temperatures of less than 0.5 degrees celcius over a period of 50 to 100 years (Diamond, 2005). Over the next 100 years, global temperatures may well reach over 4 degrees above pre-industrial. Global temperatures have not reached these levels since the middle of the Miocene epoch (14 million years ago).  


Anthropogenic climate change is unfortunately a significant risk to the long term continuation of human society on earth, as we know it.


Modern Climate Change History

A carbon based mechanism for climatic warming was proposed by Svante Arrhenius in 1896. Experimental evidence confirming a pattern of continually increasing atmospheric carbon dioxide levels was published in 1960, by C. Keeling.

By the late twentieth century, acceptance and understanding of climate change science had spread through the scientific community.

Today the broader community is now generally aware of the link between atmospheric carbon compounds and increasing global temperatures.

What is perhaps far less well understood by the broader community is how our emissions to date have already "locked in" future generations to global tempertures well above the levels generally considered to have manageable impacts on natural and agricultural ecosystems.

General scientific consensus is that the ecological and societal impacts of a global average temperature increase of between 1.5 and 2.0 degrees will be create many challenges, but should still be managable.


Recent attempts at global co-operation to reduce the causes of climate change, such as commitments made at the Paris COP 21 UN Climate Summit, have produced strong rhetoric around capping global temperature increases to 2.0 degrees above pre-industrial, with an aspirational goal of 1.5 degrees.  
 
Unfortunately climate science is clearly showing that the Paris COP 21 temperature targets are not actually possible.


So How Are We Going with Climate Change Mitigation?

In 2016, global average temperatures reached 1.0 degree above the adopted 1870 baseline year for the first time, (UK Met Office, 2016).  As the industrial revolution actually began in 1750, warming that occurred between 1750 and 1870 (0.2 degrees) also needs to be accounted for, so average temperatures in 2016 were actually 1.2 degrees celcius above a "genuine" pre-industrial baseline (Dunlop, 2016).

Further temperature increases are already "locked in", as temperature increases lag significantly behind  greenhouse gas emissions due to temperatue stabilisation from melting ice, ocean temperature stratification and a geological heat sink effect. Temperature lag is significant, estimated as approaching 40 years, which is currently equivalent to around 0.6 degrees celcius, (The Conversation, 2014).  

A further temperature increase can be expected when reflective sulphate pollutants from coal fire power stations are removed from our atmosphere, as these power stations are eventually decommissioned. This increase has been estimated at around 0.5 degrees celcius, (Mann, 2015).  

Greenhouse gas emissions to date are expected to cause warming of approximately 2.3 degrees celcius above pre-industrial, even if greenhouse gas emissions were to end overnight. 



So where to from here?  

If greenhouse gas emissions continue in accordance Paris COP 21 commitments, (i.e. full fossil fuel use being phased out by 2100), temperatures can be expected to be around 4 degrees celcius above pre-industrial by early next century.
Copyright S. Brink.
Greenhouse gases trap more infrared radiation
causing an increase in temperature.
Global temperatures are now 1.0 degree above the adpted 1870 baseline (UK Met Office, 2016).
Global fossil fuel use continues to increase.
Climate Change Impacts Under COP21
2025


2050


2075


2100

.....

2200
Great Barrier Reef Lost
Arctic Sea Ice Gone
Extreme bushfire conditions each summer in Southeast Australia
1.0m-1.5m sea level rise​​​1
4.0 deg. above pre-industrial
5m-10m sea level rise
Note 1:  NYC Panel on Climate Change, 2015
Significant Ecosystem Changes are Expected with a 4 Degree Increase in Global Temperatures
​​
The consequences of a 4 degree celcius temperature increase above pre-industrial are immense.  Widespread agro-economic, ecological and even human population collapses, are possible, and perhaps even likely? 


Copyright S. Brink.
Temperature Projections  Under Various Greenhouse Gas (GHG) Emission Scenarios 
What can we do about climate change?


The climate change challenge can seem huge. How can we as an individual, a community and even as a country, make any significant contribution to such a huge global challenge? Society, as we know it, has been developed by utilising cheap abundant fossil fuels. We do have some energy alternatives, but the economic, strategic and geopolitical complexities of transitioning to "low carbon" energy sources have been largely unresolvable to date.

One area of climate change mitigation often overlooked in popular debate is the potential role of "enabling technologies". A new technology could potentially have a very significant positive impact on our global climate future, by improving the availability of a cost effective, low carbon energy technologies that can provide additional "energy shift" alternatives to non-carbon sources.  

An "Energy Shift" to a low carbon future will ultimately need a co-ordinated global strategy. Developing new cost effective low carbon technologies could make it far more attactive for governments to pro-actively implement a full global shift to non-carbon energy alternatives.
  
But Aren't We Due for
an Ice Age?


Ice core data shows temperature variations in the past 10 million years have varied between the pre-inductrial average  temperature and approximately
8 degrees below this.
At some stage we are most like to return to cooler temperatures, but large temperature transitions have, in the past, been relatively slow, occuring over thousands of years, so such a transition is highly unlikely to make any significant contribution to resolving the current climate change crisis.
 
Perhaps our best realistic change of mitigating climate change is the development of new, very low cost, zero carbon energy technologies in the near future, that will give global policy makers the confidence to implement a full global phase out of greenhouse gas emissions before 2050, limiting global warming to around 3 degrees above pre-industrial.


References:
Diamond, J., 2011, Collapse: How Societies Choose to Fail or Succeed,
Revised Edition, ISBN-10: 0143117009, ISBN-13: 978-0143117001, first published in 2005.
Dunlop, I., 2016, ​​​Engineers Australia Presentation - Our Climate Emergency
Live preentation and webinar

UK MET Office, 2016, ​​​Global climate in context as the world approaches 1°C above pre-industrial for the first time,  www.metoffice.gov.uk, accessed 20/12/16
Mann, M, 2015, ​​How Close Are We to ‘Dangerous’ Planetary Warming?
The Huffington Post, 12/23/2015 03:37 pm ET | Updated Dec 23, 2015
The World Bank, 2012, ​Turn Down the HeatNew Report Examines Risks of 4 Degree Hotter World by End of Century
Accessed via www.worldbank.org
New York City Panel on Climate Change, 2015, REPORT: Sea Level Could Rise by 6 Feet in New York by 2100.
publichealthwatch, accessed 21st Dec 2016, publichealthwatch.wordpress.com

The Conversation, 2014, What would happen to the climate if we stopped emitting greenhouse gases today?
Published at: theconversation.com