Can we avoid ‘dangerous’ global warming?
The most pressing scientific question and political challenge about
global warming at present is this: can we avoid ‘dangerous’ global
warming, and prevent it reaching levels beyond which it will become
irreversible?
This is the key question this essay attempts to address, and
whether technological solutions really are the panacea they are so
often made out to be. In doing so, it touches upon some themes in the
Al Gore film and three books under consideration, including on some
major impacts in India.
The sum total of all human activity generates 7.2 billion tons of
carbon, or about 26.4 billion tons of carbon dioxide a year from fossil
fuels currently, according to the Fourth Assessment Report of the
Intergovernmental Panel on Climate Change (IPCC) published this year.
Though transport is one of the fastest growing culprits, it
presently accounts for only about 14% of CO2 and other greenhouse
emissions that human activity is generating each year. The other big
sources are electrical power (28.5%), deforestation (18%), industry
(14%), even agriculture (14%).
Warming of the earth
Over millenia, due to agriculture and deforestation carried out by
ancient and medieval societies, CO2 levels in the atmosphere inched
along from 260 parts per million (ppm) to about 278 ppm until the time
of the Industrial Revolution.
However, since the mid-eighteenth century, CO2 has jumped to 384
ppm, much of it in the past few decades. As the excellent website realclimate.org
recently explained, adding the warming (and cooling) effects of other
emissions – primarily methane (CH4) and nitrous oxide (NO2) but also
including ozone, black carbon, etc – that figure stood at the
equivalent (CO2e) of about 375 ppm in 2006, and is going up by at least
2 ppm each year.
As a consequence, the Earth’s average temperature has risen about
0.8 degrees C since the Industrial Revolution, reaching 14.5 degrees C
in 2005. This seemingly mild rise has already caused lands to be
nibbled by rising sea levels in the Sunderbans and the Gujarat coast,
the 2005 floods in Bombay which killed a thousand people, Himalayan
glaciers to recede, and rainfall patterns to change.
According to the UN, 66 million people were affected by floods
this year in South Asia alone. What used to seem ‘natural’ phenomena
are not natural any more, as Bill McKibben lamented in The End of Nature nearly 20 years ago.
The problem, as Paul Brown explains in Global Warming: The Last Chance for Change,
is that there’s more warming in the pipeline. There’s a lag of about
25-30 years between greenhouse gases being emitted and the full effects
of their warming. So the recent climate chaos is actually the
consequence of emissions in the late 1970s. The full effects of more
recent emissions, including from China’s coal-based power stations that
some are suddenly and rightly concerned about, will be felt in the
years to come.
We are committed, Brown writes, to a further 0.7 degrees C. That
would add up to 1.5 degrees C above pre-industrial levels. At 1.5
degrees, 18% of the world’s species will die, and 400 million more
people worldwide will be exposed to water stress.
It gets worse. As the Earth gets warmer, it will trigger off
certain ‘feedbacks’, which could be understood as the Earth’s systems
themselves contributing to warming: as Arctic ice melts, there will be
less of it to reflect heat, warming further, melting more, and so on.
Melting of Antartic and Greenland ice sheets
Warmer Antartic and Greenland ice sheets will create meltwater on
the surface which, being darker than ice, will absorb more heat.
Oceans, which currently absorb a lot of the CO2 we emit, will take in
less, and warmer soils will trigger off metabolic processes that allow
carbon dioxide in soils to escape. Melting permafrost in the Arctic
Tundra will release methane, of which there are 70 billion tons, and
methane has 23 times the warming potential of CO2.
These processes have already begun. Arctic ice was 1 million
square km less in 2007 compared to the earlier lowest in recorded
history. Waters from melting ice-sheets in Antartica are flowing
through moulins to the bottom of the ice sheets lubricating them
towards the sea. CO2 escaping from warmer soils has been recorded in
England and Wales. Surveys in 2005 suggest methane has already begun
escaping from the melting Arctic.
It’s fairly widely accepted that were the Earth to become roughly
2 degrees warmer than pre-Industrial times, it could trigger off
tipping points in the Earth’s systems: for instance, melting polar ice
could become an irreversible process. It could catalyse these feedbacks
on a scale so massive that global warming could effectively get out of
human capacity to control the process. There is a fair chance of
reaching 2 degrees if greenhouse gases are allowed to build up to
roughly 450 ppm CO2e, just 75 units from the present. Some say we have
barely about 20 years to prevent dangerous global warming.
The UK’s Stern Review puts the date at 2035, neither of which are
very much time considering the magnitude of the problem at hand. James
Hansen of NASA’s Goddard Institute for Space Studies – one of the
world’s leading climatologists – has said we have until 2015, less than
ten years.
An inconvenient truth
Al Gore’s An Inconvenient Truth deals with some of the
phenomena wonderfully: melting polar ice, receding glaciers, more
intense hurricanes, and a whole range of other serious facets of global
warming.
Barring overstating one link between CO2 rise and the magnitude of
future warming, its science is largely solid and its complexity
presented lucidly. What it doesn’t do, however, is underline this
urgency I’ve mentioned above. Additionally, its politics is flawed,
both in conceptualising the problem and in the partial solutions he
presents at the end (on which more later).
But then I don’t expect much in terms of political solutions from
almost-Presidents. Yearly US emissions rose from 5,057 million tons of
carbon dioxide (in 1992) to 5,823 million tons (in 2000) during the
years that Gore was Vice President, a rise of 15% (US Energy
Information Administration data). Influenced by the oil and timber
lobby, thousands of acres of forest lands and whole mountain ranges
were denuded, 24 million acres of the National Petroleum Reserve opened
out to oil drilling.
His film ignores the fact that entrenched political systems and
powerful corporate processes, that have got us where we are in the
first place, transcend individual preferences. But the key point about
global warming currently is the very short time we have to deal with
the problem, and the film misses out this crucial message.
This essay takes off from the following:
Al Gore/ Davis Guggenheim (director), An Inconvenient Truth, 2006, 100 mins.
Paul Brown, Global Warning: The Last Chance for Change, Dakini Books, 2006, 320 pp.
Sushil Kumar Dash, Climate Change: An Indian Perspective, Centre for Environment Education/ CUP, 2007, 262 pp.
Thomas E. Lovejoy and Lee Hannah (editors), Climate Change and Biodiversity, TERI Press, 2006, 418 pp.
This essay was originally published in Biblio, December 2007.
by Nagraj Adve
Source: http://southasia.oneworld.net/article/view/156795/1/