Monday 8 September 2014

Why we do what we do. Catastrophic Climate Instability.

The Intergovernmental Panel on Climate Change (IPCC) is the leading international body for the assessment of climate change and was established in 1988 to provide the world with a clear scientific view on the current state of climate change and its potential environmental and socio-economic impacts.  It is open to all member countries of the UN and WMO with currently 195 countries represented.  1000’s of scientist contribute to the IPCC work as authors, contributors and reviewers and NONE of them are paid for their contributions!

More information on the structure and governance can be found here (http://www.ipcc.ch/index.htm) , but the point I am trying to make is that the body as a whole and its reports should be considered apolitical and representing the scientific consensus on the current state of climate change.  The first assessment report of the IPCC was published in 1990.  In the executive summary it states:

“... there is a natural greenhouse effect which already keeps the Earth warmer than it would otherwise be... emissions  resulting from human activities are substantially increasing the atmospheric concentrations  of greenhouse gases carbon dioxide, chlorofluorocarbons and nitrous oxide.  These increases will enhance the greenhouse effect, resulting on average in an additional warming of the Earth’s surface which will further enhance the warming of the main greenhouse gas, water vapour.”

So firstly it was recognised that the Earth requires some “greenhouse” gases in order to maintain a habitable environment for humans and non-humans.  But it was already recognised in 1990 that we were contributing more gases from our activities than was needed to stabilise mean global temperatures.

“These ‘long-lived’ gases adjust only slowly to changes in emissions meaning present rates of emissions will commit us to increased concentrations for centuries ahead.  The longer emissions continue to increase, the greater the reductions will be needed to stabilise these gases at a given level.  These gases would require immediate reductions in human activities of over 60% to stabilise their concentrations at today’s (1990) levels.”

Immediate reductions were needed in 1990 in order to stabilise these gases.  Sadly that didn’t happen!

“Under Business As Usual (Scenario A) emission of greenhouse gases, a rate of increase of global mean temperature during the next century of about 0.3°C per decade... which will likely increase global mean temperature by 1°C by 2025 and 3°C by end of the century... we also predict a rise in global mean sea level of 20cm by 2030 and 65cm by end of the century.”

BUT, also mentioned in the summary was the fact there will be SIGNIFICANT regional variations and all of this can trigger both positive and negative feedback loops, which will exacerbate already deteriorating conditions further.  For example, increased temperature in one region, could lead to reduced rainfall, deforestation and then desertification (positive feedback).  This removes a critical carbon capturing device, a tree, but also releases all the stored carbon from the tree into the atmosphere! Double whammy!

More recently, you may have read about a “pause in mean global temperature increase” in a lot of newspapers.  The argument then being made (incorrectly) that global warming is stopping altogether!  This simply is not the case.  A negative feedback has occurred ameliorating some of the warming of the atmosphere; this negative feedback has been the oceans.  70% of the Earth’s surface is covered with them and they appear to have been absorbing a lot of the warming from the late 90’s.  Great, temporarily for humans, but not so for non-human species like corals, shellfish, algae, plankton and fish in general as heating causes acidification of the oceans!

Other problems with oceans taking on board all this heat is they will give up some of this energy in the form of water vapour, which forms more robust and violent storms (do you all remember the winter of 2013/2014) illustrating the premise stated by the original authors that regional variations could be SIGNIFICANT.  This heating also contributes to greater reduction of the ice cover at the poles (positive feedback), reducing the albedo effect (reflection of sunlight by the white icy surface) and increasing the absorption of sunlight (energy) by the oceans.

By the end of 2014 the IPCC will be releasing its fifth assessment report.  24-years on from their original report, it’s interesting to compare what was said then, with what they are saying now.  You can get a copy of the Summary for Policymakers (http://report.mitigation2014.org/spm/ipcc_wg3_ar5_summary-for-policymakers_approved.pdf) but I will summarise some of the key findings.

Warming of the climate system is unequivocal, and since the 1950’s, many of the observed changes are unprecedented over decades to millennia."

Each of the last three decades has been successively warmer at the Earth’s surface than any preceding decade since 1850.  In the Northern Hemisphere, 1983-2012 was likely the warmest 30-year period of the last 1400 years.”

“Over the last two decades, the Greenland and Antarctic ice sheets have been losing mass, glaciers have continued to shrink almost worldwide and Arctic sea ice and Northern Hemisphere spring snow cover has continued to decrease in extent.”

“The rate of sea level rise since the mid-19th century has been larger than the mean rate during the previous two millennia.”

“The atmospheric concentrations of carbon dioxide, methane and nitrous oxide have increased to levels unprecedented in at least 800,000 years... the ocean has absorbed about 30% of the emitted anthropogenic carbon dioxide, causing ocean acidification.”

Human influence on the climate system is clear.  This is evident from the increasing greenhouse gas concentrations in the atmosphere, positive radiative forcing, observed warming, and understanding of the climate system.”

“Continued emissions of greenhouse gases will cause further warming and changes in all components of the climate system.  Limiting climate change will require substantial and sustained reductions of greenhouse gas emissions.”

“Changes in the global water cycle in response to the warming over the 21st century will not be uniform.  The contrast in precipitation between wet and dry regions and between wet and dry seasons will increase.”

“The global ocean will continue to warm during the 21st century.  Heat will penetrate from the surface to the deep ocean and affect ocean circulation.”

“Cumulative emissions of CO2 largely determine global mean surface warming by the late 21st century and beyond.  Most aspects of climate change will persist for many centuries even if emissions of CO2 are stopped.” (ALL MY EMPHASIS)

You have to bear in mind, that these statements are released by sober, conservative, scientific people with no political affiliations or vested interests and require a complete consensus for the reports to be released.  These statements are likely to have been influenced by policy-makers who have quibbled over terms and "scare-mongering", so quite probably are underplaying the threats!

What does this mean for La Fieffe, a small holding in Europe?  Well, we simply don’t know, but we can be fairly sure that an unstable atmosphere, with more heat and more water vapour will make our current predictable seasons hugely unpredictable.

How do you grow food if you can’t be sure of stable and predictable year-on-year temperatures, rainfall and sunlight?

How many crop failures can our small-holding deal with?  More importantly how many crop failures can the big farming and food selling giants cope with before the populace becomes desperate as shelves are no longer full?

Will this instability of the climate lead to instability of the people, unsure of where they will get support feeding their families?  Are policy makers considering this when they prevaricate about committing to carbon-reduction targets?

What are you doing to reduce your carbon footprint?  It isn’t just a 21st century fad.  WE, the “pampered 20%”, need to do something about our consumption.  To not act, condemns my children and yours to a unpredictable, unstable and probably miserable future... think about that!

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