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Climate change: An update December 5, 2012

Posted by Andreas in Climate change, Column, Environment, Global warming.
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Climate change: An update

(This column was first published on 2012-11-26 at News24 here)

There has been overwhelming scientific consensus on climate change for years. A recent survey found that out of 13 950 peer-reviewed scientific papers published on the topic between the beginning of 1991 and the beginning of last month, only 24 argued against human-induced global warming.

The amount of research generated in this field is massive, but little of it ever makes it into the mainstream media (I don’t know if that’s because editors are bored with the subject or just overwhelmed by it), which is why I thought it would be a useful exercise to highlight a few of the most recent findings and forecasts. This is by no means a comprehensive review, merely a bullet-pointed précis to give you an inkling of how much trouble we’re in. Click on the links for more details on the assorted items.

– Records of average global temperatures show a consistent warming trend for the last three decades and according to the UN’s World Meteorological Organisation, 2012 is expected to be the ninth warmest year since records began in 1880.

– Atmospheric CO2 concentrations reached a record high of 390.9 parts per million in 2011 – that’s a 40% increase since the start of the industrial revolution.

– Ice is melting ever more rapidly in the Arctic and the Antarctic.

– Sea level rose by about 3.2mm per year between 1993 and 2011, significantly faster than previously estimated. Highlighting the long-term impacts of climate change, worst-case scenarios predict up to 6.8 metres of sea level rise by the year 3000.

– This year, the inhabitants of Vunidogoloa on the Fijian island of Vanua Levu became some of the first people in the world to be relocated to higher ground because seal level rise has made their seaside village uninhabitable.

– The destruction of mangrove forests, salt marshes, sea grass beds and other coastal ecosystems releases between 150 million and 1.02 billion tons of CO2 annually, several times more than previously thought.

– The world’s largest reinsurance company, MunichRe, has warned that risk from climate change related natural disasters is rising globally and local insurers agree. Insured losses from such events have risen from $9bn in the 1980s to $36bn in the 2000s.

– Significantly reduced rainfall during Asia’s annual monsoon season is predicted for the next two centuries with potentially devastating impacts on agriculture in the region.

– In November, the planet’s most powerful investors, managing some $22.5 trillion between them, wrote an open letter to the governments of major countries, warning that climate change is a major threat to the world economy.

– Slashing 1.6% off the global GDP, climate change has been estimated to cost the world economymore than $1.2 trillion every year and according to a recent World Bank report, it’s the poorest countries that will suffer most.

– The effects of climate change on the world’s oceans are forecast to lead to a severe drop in fish stocks and a shrinkage of 14-24% in the size of adult fishes by 2050.

– Pollen counts are expected to more than double by 2040 and in combination with highly allergenic new strains of pollen from invasive species, hay fever season may be extended by weeks.

– With the disappearance of much of the bamboo they feed on, the natural habitat of the giant panda in China may be lost by the end of the century.

– Diseases carried by mosquitoes, ticks, fungi and algae, including Lyme disease, the West Nile virus, Chikungunya Fever, Rift Valley Fever and Dengue Fever are already spreading to areas where they were not found in the past.

– The collapse of the southern Caribbean’s sardine fisheries during the past decade has been linked to climate change.

– Wild Arabica coffee, indigenous to East Africa, may become extinct within 70 years.

– While warming temperatures and increased levels of CO2 in the air may improve agricultural production in some regions, an 8% average decrease in the yield of eight major crops, including maize, millet, sorghum and wheat, is predicted for Africa and South Asia by the 2050s.

 Andreas freelance writer with a PhD in geochemistry. Follow him on Twitter: @Andreas_Spath

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Comments»

1. cptwayne - December 11, 2012

Yes, I go along with human induced global warming, but not caused by CO2! You see, the total greenhouse gases may not have increased If CO2, in fact, displaces atmospheric water vapor. So the total remains the same. Can anyone tell me differently or that they can accurately measure the world’s atmospheric water vapor? Yet everyone claims the GHGs are increasing. This is really only an assumption. CO2 is increasing. But what about the other 98%?
The warming trend for the last few decades appear rather tame. I see no correlation with temperature and rising CO2, except for the fact the temperature goes up first. As for the melting glaciers, the atmospheric particles, extra heat released from the Earth’s crust (as the glaciers melt) and the reflective properties of CO2, lack of snow, nearby cities and dryer air all play their role.
Oceans rising faster than usual. Don’t bet on it. Most tidal gauge locations show no sign of acceleration in the last 80+ years.The main contributor to changes in the volume of the ocean basins is likely the presumed sinking of the ocean floor due to the input of meltwater from ice sheets of long ago. So, this accounts for 1/3 of the 1.8 mm/year avg. rate of coastal sea-level rise (SLR) for the last century. Putting it another way, 0.3 mm/yr is usually added to satellite-measured rates of SLR prior to being reported. Those adjustments cheat the meaning of “sea level rise” and inflates the satellite SLR reports by more than 10%.
Note too that sea surface temperature changes do not affect coastal sea levels at all. Gravity balances mass, not volume, so when ocean surface waters warm or cool, the resulting density changes have only local effects, rising or sinking in place, like icebergs. Only if there are density changes in the ocean depths can it affect coastal sea levels, and no such changes are thus far observed.
Is Antarctica losing ice mass? According to ICEsat measurements, Antarctica is gaining ice mass. SLR info synopsis from: “Sea Level Rise Fallacies” by Anthony Watts.


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