Tackling food security with a growing population, climate change and peak oil

With a growing population and improving diets there is a need to double our food supply by 2050. Identify three measures you would take to meet this demand. Identify one of your measures from your list and post your solution into the discussion - be prepared to defend your choice!

That is a big question to throw in a climate change course. I am presently doing an online course - Climate Change: Challenges and solutions - offered by the University of Exeter (UK). So please indulge me as I also use this blog for some climate course work. This article is for week 6, section 6.5 of the course on 'Tackling food security'.

Food security is one helluva big area to try and come to terms with. Earth's population is just over 7 billion people. It is projected by the United Nations in a June 2013 report on global population to reach 9.6 billion people by 2050, although some commentators like David Merkel think it may peak at 8.5 billion around 2030 due to officials underestimating the fall in the fertility rate.

Currently, at least one billion people are constantly hungry or living under the threat of hunger.

Agricultural productivity of the last century has been brought about by the energy input from fossil fuels. There is a strong recent correlation between soaring food costs and soaring oil costs. With Peak oil, energy costs can expect to increase much further, placing further costs on food production. A FAO 2011 report says: "Commodity prices tend to be linked with global energy prices. As energy prices fluctuate and trend upwards, so do food prices".

ExClimate: Experiment shows coral reefs in peril in a high CO2 world

Professor Ove Hoegh-Guldberg takes us through and explains a controlled experiment his Institute is conducting in coral reef ecosystem reaction to various temperature and carbon dioxide environments.

Hoegh-Guldberg is Director of the Global Change Institute at the University of Queensland and an important authority on tropical marine biology, coral reef ecosystems and climate change.

He argues that Coral Reef ecosystems have already changed significantly from pre-industrial times, and will change even further as human carbon emissions increase in the atmosphere with many species likely to be pushed to extinction due to heat stress and ocean acidification from anthropogenic climate change.

ExClimate: Greenland's Jakobshavn Glacier revs up with climate change

A "glacial pace" can no longer be used to describe the speed of the Jakobshavn glacier in Greenland. The latest study of Jakobshavn Isbræ (Jakobshavn Glacier) from Greenland reveals the glacier is setting new speed records. In the summer of 2012 the glacier reached a record speed of more than 17 kilometres per year, or over 46 metres per day. This is an unprecedented speed for a glacier and appears to be the fastest ever recorded for any glacier or ice stream in Greenland or Antarctica, according to a new study published in The Cryosphere.

The glacier discharges ice bergs in calving events from West Greenland and it's calving face continues to retreat over a deep depression in the fjord, which adds to it's instability.

“We are now seeing summer speeds more than 4 times what they were in the 1990s on a glacier which at that time was believed to be one of the fastest, if not the fastest, glacier in Greenland,” says Ian Joughin, a researcher at the Polar Science Center, University of Washington and lead-author of the study: Brief Communication: Further summer speedup of Jakobshavn Isbræ.

Exclimate: Are recent global temperatures predicted by climate models?

This article is a little bit of a tangent to my regular articles. I am presently doing an online course - Climate Change: Challenges and solutions - offered by the University of Exeter (UK). So please indulge me as I also use this blog for some climate course work. This article is for week 3, section 4.4 of the course on 'IPCC Fifth Assessment Report'.

The IPCC recently published their Fifth Assessment Report (2013). Does the recent change in global temperatures reflect the predictions of climate models? Search for other feedback in the media and focus on the role of climate models and then try to address the discussion question: Does the recent change in global temperatures reflect the predictions of climate models?

An interesting question, because recent global mean surface temperatures over the last 15 years from 1998 show only a very slight warming trend. In the HadCRUT4 temperature data series the trend is 0.04°C per decade over 1998–2012, compared to 0.11°C per decade over 1951–2012. This is used by climate sceptics to argue that 'global warming has stopped'.

So have climate models predicted this slow down in temperatures?

Not per se. But global climate models do include natural variability cycles as part of their long term average trend. In some periods of a similar length of time warming is greater than the average, and in some it is less or even shows a measure of cooling. This can be seen even in the last 100 years. So, yes, this recent slow down in global temperatures over the last 15 years forms part of long term climate model trends.

ExClimate: Climate modelling Australian climate impact scenarios

This article is a little bit of a tangent to my regular articles. I am presently doing an online course - Climate Change: Challenges and solutions - offered by the University of Exeter (UK). So please indulge me as I also use this blog for some climate course work. This article is for week 3, section 3.4 of the course on 'Your Warming World'.

The USGS provides an application, the CMIP5 Global Climate Change Viewer, for anyone to access to do research, with the proviso any results that are published should remain open and non-commercial. This application provides projections for two variables: temperature and precipitation. It can be run for annual mean or monthly results, using the mean model or a selected specific global climate model, and for different projected emissions pathways (Representative Concentration Pathways or RCP) for a particular period.

It might sound complicated, but the tool is relatively easy to use, but takes a little while to figure out all the bells and whistles. I did an initial investigation and produced some basic results, but after sleeping and some reflection decided to investigate further not only global climate model projections for the planet, but also regional projections for the South East Asia and the South Pacific and Australia in particular.

• Representative Concentration Pathways (RCP)
  
• First model results: average model mean RCP8.5 for 2050-2074
  
• Global model mean Business As Usual results for 2071-2095
  
• GFDL-ESM2M Single model results using RCP8.5 for 2071-2095
  
• Introduction to Australian climate projections
  
• Projections for Australia using GFDL CM2.1 global climate model
  
• Projections for Australia using ECHAM5/MPI-OM global climate model
  
• Conclusions
  

ExClimate: Week 3.3 - Extreme events and climate Discussion

This article is a little bit of a tangent to my regular articles. I am presently doing an online course - Climate Change: Challenges and solutions - offered by the University of Exeter (UK). So please indulge me as I also use this blog for some climate course work. This article is for section 3.3 of the course on State of the climate extreme events.

1. Climate event for 2012 - Cat 4 cyclone Evan in South Pacific devastates Samoa and Fiji

Select an extreme weather event from 2012 (list provided). Does this provide further evidence of climate change or does it add more complexity to the issue?

I chose severe Tropical Cyclone Evan, a category 4 storm which devastated Samoa and Fiji in December 2012. While this particular storm was primarily part of natural climate variability, it fits the trend for more intense tropical cyclones which climate models and climate physics tells us is likely to occur.

Tropical cyclones on a global level are forecast to stay at about the same frequency, but with a greater number of intense tropical cyclones/hurricanes/typhoons occurring, according to the 2011 IPCC SREX Summary for Policymakers report.

ExClimate: CO2 Passing 400 parts per million, a comparison with the Pliocene

The Pliocene period, 3 to 5.3 million years ago, was the last time CO2 was at 400ppm. Investigate what the temperatures were during this time period and compare them to today. Using your knowledge from the course so far, what could explain the changes?

2013 was the first time planet Earth passed 400ppm carbon dioxide in the atmosphere since the Pliocene perod. Instruments at the Mauna Loa Observatory in Hawaii have been measuring atmospheric CO2 and other greenhouse gases for over 50 years. Other sites like CSIRO's Cape Grim observatory in Tasmania and New Zealand's National Institute of Water and Atmospheric Research (NIWA) at Baring Head Station near Wellington also take baseline measurements of atmospheric greenhouse gases.

The Keeling curve shows the rising levels of atmospheric carbon dioxide trend and is one of the most well known climate graphs. It was named after Charles Keeling from the Scripps Institute for Oceanography who started measuring CO2 at Mauna Loa in 1958 and continued up to his death in 2005. The graph clearly shows the northern hemisphere season cycle of carbon dioxide as part of the biological seasonal processes as CO2 is taken up by vegetation in Spring and Summer, then expired in Autumn and Winter, but the long term trend has been a gradual rising of CO2 by about 2ppm per year.

The significance of reaching 400ppm is that the planet has not seen this level of carbon dioxide for 3 to 5 million years, in the Pliocene Period. It was a warmer world then. By examining this geological period we can gain some insight on what we might expect to happen to temperatures, sea levels, the impact on ice sheets, and some signs of how our climate might change later this century and further into the future.

ExClimate: The Ice Albedo Feedback mechanism and Snowball earth

This article is a little bit of a tangent to my regular articles. I am presently doing an online course - Climate Change: Challenges and solutions - offered by the University of Exeter (UK). So please indulge me as I also use this blog for some climate course work. This article is for section 2.3 of the course on Snowball earth events that have ocurred in the distant past.

No one is sure what precipitated the onset of snowball earth events. The oldest snowball earth event occurred approximately 2200 million years ago. The most recent event ended about 635 million years ago and is thought to have lasted 6 to 12 million years. Very basic life managed to survive at least the most recent snowball earth event.

The earth's orbit around the sun, it's axial tilt, and wobble all have different millenial cycles which can affect the amount of solar radiation being absorbed by the earth. Earth’s orbit changes from near circular to oval shape on a 100,000-year cycle (eccentricity). Earth’s axis is tilted and is presently at 23.5 degrees. It varies between 21.5 and 24.5 degrees every 41,000 years (obliquity - Milankovitch cycles). As the Earth spins it wobbles on its axis toward and away from the Sun over the span of 19,000 to 23,000 years (precession).

What caused the earth to go into a giant snowball is still being debated in scientific circles. A number of theories have been advanced including :

• a reduction in solar output,
  
• the Earth passing through rare space clouds,
  
• a combination of high obliquity in the Earth's orbit, orbital eccentricity or precession;
  
• Lithospheric weathering reducing atmospheric carbon causing planetary cooling
  

Climate Geo-engineering study on sulphate injection shows Hydrological disruption to rain and severe drought

While politicians have effectively dithered on robust action to reduce greenhouse gas emissions over the last 20 years we are hearing more about geo-engineering proposals to moderate rising temperatures. But the latest study from the University of Reading scientists modelling solar radiation management, and in particular atmospheric aerosol injection - one of the easiest geo-engineering proposals to do at large scale - says such a project would result in a major decrease in tropical rainfall and an increase in drought in many regional areas.

The Reading University study concentrated on the consequences on geo-engineering methods to change the solar radiation reaching the earth: through mirrors above the atmosphere; and injecting sulfate aerosols into the atmosphere to reflect solar radiation. The first could prove hideously expensive and is at the moment impractical, but the second method is quite achieveable at reasonable cost.

The study - Weakened tropical circulation and reduced precipitation in response to geoengineering (Full paper) - looks at aerosol injection in particular and the projected impacts. It was published in Environmental Research Letters.

Related: Yale Environment360: Solar Geoengineering: Weighing Costs of Blocking the Sun’s Rays (9 Jan 2014)