Saturday, 6 April 2013

Global warming will change the world by 2100

by Zeeshan Hasan

What will the world look like in the year 2100? Climate scientists are now able to answer a substantial part of this question, and the projections they have for us are unsettling. Yet few people are aware of the findings of climate science due to an immense smokescreen of doubt which the fossil fuel lobby has raised around global warming research. These issues are dealt with in Global Warming and Political Intimidation: How Politicians Cracked Down on Scientists as The Earth Heated Up by Raymond S. Bradley (published by University of Massachusetts Press in 2010). Bradley is Distinguished Professor of Geosciences at the University of Massachusetts at Amherst in the United States.

Our modern world runs mainly on fossil fuels like coal, oil and gas; burning these produces carbon dioxide, which traps heat from the sun and causes global warming. But whether or not human carbon dioxide emissions had actually produced real man-made global warming was a matter of debate among scientists for decades. In 1998, Bradley and his co-researchers published their 'hockey-stick graph' which depicted a 1,000-year decrease in average world temperatures, which was suddenly reversed in the 20th century. The only explanation for the sudden warming shown in the hockey stick was post-Industrial Revolution global warming. The 'hockey-stick graph' effectively proved that burning of coal, oil and gas has already changed the planet, and is changing it further as you read this article.

The publication of the 'hockey-stick graph' set off a tsunami of activity among the lobbyists of the fossil fuel industry. In the US, Congressman Joe Barton of Texas, who was on record as having received over half a million dollars from the fossil fuel industry during his 2004 Congressional race, launched a government-led witch-hunt, accusing Bradley and his co-researchers of fraud. Fortunately, other members of the US Congress opposed this blatantly political attack on science. However, attempts to discredit Bradley and his research continued; in 2009, hackers stole e-mails from the Climate Research Unit of the University of East Anglia in the UK in an incident dubbed 'Climate-gate' by the press. An army of right-wing bloggers, journalists and other supporters of the fossil-fuel industry claimed that in one of the emails, another climate scientist had admitted that Bradley and his co-researchers had used a 'trick' to 'hide the decline' in world temperature, and that the research was therefore false. Numerous academic enquiries were launched against Bradley and his co-researchers; ultimately none found any wrongdoing on their part or mistakes in their work. However, widespread coverage of the Climate-gate email hacking had already served to discredit climate science and global warming in the public eye. Though based entirely on false accusations, Climate-gate contributed to the failure of international climate talks on carbon emissions.

What are the findings of climate scientists that the fossil fuel industry has tried so hard to discredit? The original 1997 'hockey-stick graph' only analysed historical temperatures over the previous 1000 years. In his book, Bradley gives an extended 'hockey-stick graph' to predict world temperatures until the year 2100, given below.

As visible from the graph, at projected carbon dioxide emissions, the world can be expected to heat up by about 3.0 degrees C by 2100. This is probably enough to melt the Greenland ice cap, raising sea levels by about 80 feet (25 metres). Such sea level rise would submerge Bangladesh and most coastal cities in the world, including New York, Los Angeles, London, Sydney, Mumbai, Kolkata and Shanghai. Food will be more expensive and famines more common as parts of Asia and Africa will become too hot for farming.

How likely is this quantity of carbon dioxide to be emitted? Bradley gives details:
"The projected temperatures are from the future scenario... which envisions carbon dioxide emissions rising to 16 billion metric tons by 2050... then declining to 13 billion by 2100... This is a ¨middle of the road¨ estimate compared to the range of scenarios considered by the IPCC." — Global Warming and Political Intimidation: How Politicians Cracked Down on Scientists as The Earth Heated Up (Page 139)
'Middle of the road' actually means that the above is an optimistic projection; it assumes that sizable reductions will be made in carbon dioxide emissions over the next few decades. So far, none of these reductions has been made, and emissions are still going up. Unless real action is taken quickly, the above projection may well be a best-case scenario. The only way to improve on this outcome is to quickly replace coal, oil and gas with solar, wind and nuclear power. Anyone who wishes to see a better future for his/her children and grandchildren needs to pressure the government to that end.

(First published on 7th April 2013 in the Financial Express in Bangladesh)

Monday, 18 March 2013

Burning coal, oil and gas may cause sudden, extreme climate change

It is scientifically established that our burning of fossil fuels and the resultant carbon dioxide emissions will result in global warming, and ultimately may cause dangerous climate change. But how fast can that happen? 'The Two-Mile Time Machine: Ice Cores, Abrupt Climate Change And Our Future' (published by Princeton University Press in 2000) by climatologist Richard B. Alley, explores climate scientists' answers to these questions. The author is Professor of Geo-sciences at the Pennsylvania State University in the USA.

Alley is one of the climate scientists who has spent years collecting and analysing ice cores; these are long samples of ancient ice which have been extracted from the two mile thick Greenland ice cap. This massive layer of ice has been forming for over 100,000 years, and is an repository of historical evidence to climate scientists. The snow deposited each year is still visible as layers in the ice, and these annual layers preserve much chemical information from which scientists can extract a record of past snowfall and temperature. Of particular importance is what the ice cores have revealed of the end of the “Younger Dryas” ice age.

'At the beginning of this book, we met the Younger Dryas, the last cold gasp of the ice age between about 12,800 and 11,500 years ago... Standing in the science trench in Greenland, I measured how thick the annual layers were in the [ice] core across the end of the Younger Dryas. I found that... many thick layers were followed by one slightly thinner layer, one scarcely more than half as thick, one scarcely more than half as thick, another slightly thinner than that, then a lot of similarly thin ones grouped around a spike of thicker ones. This is most directly explained as a twofold change in three years, with most of that change in one year... So I cannot insist that the climate changed in one year, but it certainly looks that way.' (pages 110-111).

So science tells us that very significant climate change can occur in just a handful of years. Similar warming may well be in store for us, given that our carbon emissions are changing the atmosphere far more rapidly than any natural process has in the past. Alley proceeds to give details of the sudden, extreme temperature change that occurred at the end of Younger Dryas ice age:

The most direct interpretation... is that the surface of Greenland warmed by about 15 F (8 degrees Celsius) in a decade or less. (page 112)

This should frighten us. This sort of warming today would mean the end of the world as we know it. Climatologists estimate global warming of 5 to 6 degrees Celsius today would render most of the world too hot for agriculture (except a narrow northern band comprising Canada, northern Europe, Russia and Siberia). Widespread famine, starvation and war would be the norm. The vast majority of humanity would almost certainly perish.

Alley's conclusions regarding the climate change which ended the Younger Dryas ice age should serve as a wake-up call. The reason that no action has been taken by governments to reduce carbon dioxide emissions and stop global warming is that climate change is assumed to be something that will happen very slowly, and thus only impact the distant future. However, this assumption is questionable given the findings of climate science. The scientific record of the Greenland ice cores shows that when climate change does occur, it can be both quick and extreme. In that case it is not just nameless future generations that our carbon emissions endanger. Rather, our addiction to fossil fuels like oil, coal and gas may well sacrifice the lives of our own children and grandchildren. All of us who wish for a better future than this need to start lobbying our governments to quickly replace fossil fuels with solar, wind and nuclear power.

(Copyright by Zeeshan Hasan. First published in Bangladesh in the Daily Star on March 19th, 2013).

Sunday, 10 February 2013

Disrupting Earth's climate is to awaken a sleeping beast

Fixing Climate; The Story of Climate Science and How to Stop Global Warming by eminent climate scientist Wallace Broecker and his co-writer Robert Kunzig is an informative look at the science of global warming as well as a summary of the options for solving it. Wallace Broecker is a professor of Earth and Environmental Sciences at Columbia University, and through his research first discovered one of the primary regulators of the planet's climate; namely the “thermo-haline conveyor,” the network of ocean currents which circulates hot and cold water over much of the Earth's surface.

A recurrent theme in Broecker's writing is his view of Earth's climate as a sleeping beast which we awaken at our peril. The relative stability of climate for the past ten thousand years (since the end of the last ice age) is exactly what allowed humans to develop agriculture and create civilisation. Thus, we have greatly benefited from the long sleep of the climate beast. However, the carbon dioxide emissions created by our modern society's dependence on fossil fuels like coal, oil and gas risk disrupting the climate and waking the climate beast. The consequences could be sudden and drastic.

Whereas we may think of climate change as being gradual and taking place over centuries or millennia, climate science has shown that drastic changes have happened very quickly in the past. A prime example is the end of the “Younger Dryas” ice age, a cold period which lasted from 12,800 to 11,500 years ago.

“The [ice] measurements ... had shown that the warming at the end of the Younger Dryas had been abrupt ... the ice layers were suddenly half as thick ... most of that change had taken place in just a few years” (page 141).

So the scientific evidence is that climate change of sufficient magnitude to end an ice age can occur naturally in “just a few years,” not centuries or even decades. This bodes ill for our future, as our burning of coal, oil and gas is now changing the carbon dioxide concentration in the atmosphere faster than any time in history. If a similarly quick global warming were to happen now, humanity would have little time or ability to adapt to it. The results would be catastrophic in terms of increased desertification, reduced food production and famine.

Aside from temperature rise, the biggest threat to Bangladesh in particular is from sea level rise. This is another area where research in climate science has made it clear that big changes can happen at a frightening pace.

In the 1980's a colleague of Broecker's, Richard Fairbanks, thought he could pinpoint a time when sea level rose twenty metres in a single century (page 171).

The above is indeed a stark contrast with the scientific conservatism of the Intergovernmental Panel for Climate Change (IPCC) assessment of sea likely sea level rise being 59 centimetres by 2100.

The IPCC scientists specifically did not take into account the recent observations of accelerated ice loss from Greenland and Antarctica -- essentially because they didn't know what to make of them (page 183).

The problem is that scientists are generally cautious by nature, and unwilling to talk about possible worst case scenarios until that outcome is virtually certain. Unfortunately, if we wait until the worst case global warming scenario is inevitable before we start doing anything, it will be too late; the climate will have already changed, and humanity will have to suffer the awful consequences. Scientific conservatism in this case is lulling the public and world governments into a misplaced sense of security. So what is to be done? The answer is clear.

Which brings us to the one absolute certainty; no significant solution to the [carbon dioxide] problem can emerge until governments worldwide, and especially that of the United States, follow the lead of Norway and the European Union and impose either an emissions cap or a direct tax on [carbon dioxide] (page 266).

Broecker's conclusion is shared by most climate scientists. To prevent dangerous climate change, carbon dioxide emissions must be reduced by replacing fossil fuels rapidly with nuclear, wind and solar energy. This will require huge investments, and the only way the money can be raised is through a carbon tax. Those of us who care about what the future holds for our children need to start thinking about how to bring about this colossal change in the world economy.

(First published in Bangladesh in The Daily Star on 11th February 2013.)