Tuesday, 22 September 2020

Solving climate change with Thorium Molten Salt Reactors (MSRs)

First published on 22nd June 2020 in the Dhaka Tribune.

The daily headlines make it clear that the world is headed for climate catastrophe, with record heat and wildfires burning much of Australia in the past year. Climate scientists warn that only a decade or two is left to avoid catastrophic global warming of over 2C, which would submerge all low-lying areas under rising seas, creating millions of climate refugees, and endanger global food production, potentially causing huge famines. 

Obviously, the world has to stop using fossil fuels, which are the root cause of climate change; Super Fuel: Thorium, The Green Energy Source for the Future by Richard Martin shows a path forward. We might have been already living in an alternate world powered by cheap, safe, and zero-carbon nuclear power if civilian nuclear energy had been allowed to develop freely without military interference. 

The terrible accidents of Chernobyl and Fukushima could have been avoided if the safer alternative of thorium-based molten salt reactors had been chosen as the basis of civilian nuclear power. Instead, we still use fossil fuels as our main energy source, and the world remains at dire risk of extreme global warming.

Martin’s book outlines the development of the “light water reactor” design which dominates the world’s nuclear industry, and how this design was driven by military concerns rather than the need for safe nuclear power. The light water reactor was used for the first commercial nuclear reactor at Shippingport, Pennsylvania in 1957, as well as the first Nautilus nuclear submarine of the US Navy in 1958. 

The common reactor design was no accident, but the result of development decisions by Admiral Hyman Rickover: In the 1950s, he headed the US naval nuclear submarine research team and also decided as a member of the US Atomic Energy Commission what shape civilian nuclear power would take. 

The advantage of the light water reactor was obvious from Rickover’s naval perspective: “The Navy had the best plumbers in the world. They knew how to design and operate pumps, bearings and valves to transport water, including water at the high pressure required for a nuclear reactor inside a submarine” (page 106). 

The selection of water as reactor coolant was dangerous, however; it created the possibility of water escaping as high-temperature, high-pressure steam, or even worse reacting with metals in the reactor to release hydrogen gas, which could then cause an explosion. So light water reactors needed large, expensive “containment vessels” to prevent steam or hydrogen explosions from releasing radioactivity into the surroundings. Thus a factor as arbitrary as the US Navy’s comfort with water-based plumbing was decisive in giving the world the inherently unsafe, yet expensive and difficult to build, light water reactor which dominates nuclear power today.

Alvin Weinberg, the head of Oak Ridge National Laboratories in the US and one of the original designers of the light water reactor, identified further safety problems; these reactors were built around a solid core containing uranium “fuel rods” which host the nuclear reactions. Slowing down the nuclear reaction requires a mechanical control system to physically move “control rods” in between the fuel rods. In a light-water reactor, any problem with the mechanical control system can cause the core to overheat and catastrophically melt down. 

To solve these issues, Weinberg and his team designed the “molten salt reactor.” As Martin says: “The only truly inherently safe reactor is a liquid-core reactor, like the molten salt reactor that was created at Oak Ridge in the 1960s. For the purposes of a reactor designer, liquid -- whether it’s water, liquid metal, or some type of liquid fluoride [salt] -- has a marvelous characteristic; it expands rapidly when it gets hot … In a liquid core reactor, as the energy of the liquid rises, it expands and naturally slows down the reaction, making a runaway accident nearly impossible … When the reactivity goes down, the reactor is essentially turning itself off”(page 73). 

This sort of passive safety (which does not require human or mechanical intervention to slow down the reaction) is missing from the light water reactors which now provide most of the world’s nuclear power.

While thermal expansion of the liquid core of Weinberg’s molten salt reactor provides passive cooling to slow the nuclear reaction, it’s still conceivable for an accident to happen due to unforeseen natural disasters such as earthquakes. However, even in the event of an earthquake or other accidents at a molten-salt reactor, the release of radioactive material into the environment and consequent damage to life and health is almost zero. 

“Fluoride [salt]-based liquid fuels have one other characteristic that makes them ideal for reactor cores: They flow. Gravity, not elaborate control systems or so-called passive safety systems, gives liquid fluoride thorium reactors their ultimate protection against a serious nuclear accident. In a power outage or mishap, a specially designed freeze plug in the reactor vessel melts and the liquid core simply drains out of the reactor into an underground shielded container, like a bathtub when the drain plug is pulled. The fission reactions quickly cease, and the fluid cools rapidly … Meltdown is impossible”(page 74).

Again, earlier generations of light water reactors lacked such a passive safety measure to limit the release of radioactivity from nuclear accidents.

Weinberg’s molten salt reactor design had another innovation; it could be run on thorium-based nuclear fuel, which is not as rare as uranium, and consequently promises to be an affordable fuel source for much longer. This is important, as nuclear fuel has to be inexpensive and readily available in the long-term for developing countries which consume increasing amounts of power.

A thorium-based molten salt reactor (also known as Liquid Fluoride Thorium Reactor, or LFTR for short) is also much more efficient with its nuclear fuel, in that it converts almost all of its thorium fuel to uranium-233 and then burns almost all of it. By comparison, a light water reactor utilizes only a tiny percentage of its uranium-235/238 nuclear fuel and so produces many times the volume of nuclear waste. 

The nuclear waste produced by thorium molten salt reactors is also much less long-lived. “While LFTRs, like every other nuclear reactor, generate fission products that are highly radioactive, their half-lives tend to be measured in dozens of years, not thousands.” (page 77). 

This means thorium-based molten salt reactors will not present the problems of storing radioactive waste for thousands of years that conventional nuclear plants face. In fact, new designs of molten salt reactors are now being researched which could consume existing stocks of radioactive nuclear waste as fuel, thus permanently removing the need for long-term storage of nuclear waste (pages 78-79).

Unfortunately, the US Navy invested heavily in light water reactors for its nuclear submarine programs; big corporations like GE and Westinghouse likewise invested heavily in marketing and constructing light water reactors around the world. 

Both these powerful groups opposed further research into alternatives like the safer molten salt reactor. The US government under Nixon short-sightedly terminated funding for Weinberg’s molten salt reactor research. Weinberg’s outspoken criticism of the dangers of the light water reactor design ultimately led him to be fired from his job as head of Oak Ridge National Laboratories. However, disasters at Chernobyl and Fukushima have shown that Weinberg was correct to be apprehensive about the safety of light water reactors.

Disasters at Fukushima and Chernobyl created panic, and have resulted in much public opposition to nuclear energy. This was a colossal mistake in environmental terms, as it has meant that countries like Germany and Japan have been replacing carbon-free nuclear power with yet more fossil fuels. 

Many environmentalists also reject nuclear power in favour of wind and solar power; however, these renewable sources are intermittent, and can’t replace continuous fossil fuel-based power without colossal investments in electrical storage batteries which are both commercially and technologically infeasible. Thorium-based molten salt reactors in every country (in fact, in every city) are thus a much more realistic solution to the climate crisis.

The good news is that in the last decade, around a dozen nuclear start-up companies in various countries have emerged, developing new designs based on the thorium molten salt reactor, with considerable research taking place at the government level in India and China as well. Hopefully, thorium molten salt reactors will soon be available to be built in countries like Bangladesh which are acutely vulnerable to global warming and sea-level rise, and desperately need greener, cheaper, and safer alternatives to both fossil fuels and conventional uranium reactors. 

One can only hope this happens before our dependence on coal, oil, and gas damages the earth’s climate beyond the capacity for human survival.

Saturday, 25 January 2020

Saving the world with carbon taxes

This article was published in Dhaka Tribune on 25th August, 2019.

Every day, the news brings fresh stories about the urgency of stopping climate breakdown. The number of record hot years over the past decade keeps climbing, along with reports of severe storms, summer heat waves and melting polar ice. And yet we continue burning coal, oil and gas every day, generating more carbon dioxide emissions and making the planet hotter. Sometimes the scale of the climate problem seems overwhelming. But the fact remains that stopping global warming is simple; it only requires implementing a policy of global carbon taxes.

Economist have acknowledged for decades that global warming is essentially a failure of the market to price fossil fuels correctly. The abundance of coal, oil and gas means their minimum price is largely determined by extraction costs from the earth, which generally results in a low price (particularly for coal, which is cheap to mine). Unfortunately, the low prices of fossil fuels don’t reflect their true cost to society: if global warming is allowed to raise the Earth’s temperature by 4 or 5 degrees Celsius over the next century as projected by scientists, it could mean the end of much of the world’s population through droughts, crop failure, famines and ultimately warfare over food and water (a pattern already seen in Syria). The long-term cost of unmitigated climate change would be almost incalculable.

The rational, economic solution is to tax fossil fuels at point of extraction or import by coal, oil and gas companies. This would increase prices of coal, oil and gas and reduce their use, and thus slow down carbon emissions and global warming. However, governments have been wary of carbon taxes as a political liability which could create both unemployment and public dissatisfaction. In France, Macron’s attempt to impose a carbon tax at the beginning of 2019 sparked the violent ‘yellow vest’ protests among low-paid workers who could not afford higher transport and heating bills.

However, there is a refinement of carbon tax policy which can solve the problem of imposing any tax burden on the poor, namely 'carbon dividends'. This is the subject of economist James Boyce’s excellent new book, ‘The case for carbon dividends’. A ‘carbon dividend’ simply returns carbon tax revenue to the public as a flat payment per taxpayer. If all carbon tax revenue is returned this way, the net economic burden of the carbon tax will be zero, and it will not create unemployment. An example is helpful here; consider a simplified population of 100 people consisting of 5 wealthy people and 95 lower-income people. As wealthy people buy more carbon-intensive goods like cars and aeroplane flights, the wealthiest 5% may have 100 times the carbon footprint and thus might each pay $1000 carbon tax (as opposed to $10 for a lower-income person who doesn't fly or drive). Total carbon tax revenue for a sample population of 100 people would be (5 wealthy people x $1000 per person carbon tax) + (95 lower-income people x $10 per person carbon tax) = $5,950. However, all taxpayers would receive an averaged equal carbon dividend of $5950/100 or $59.50 each. That means that the wealthiest 5% of people would pay a net tax of ($1000 carbon tax - $59.50 carbon dividend) = $940.50 each, which gives them a powerful incentive to reduce their fossil fuel consumption. On the other hand, the lower-income 95% would receive a net benefit of ($59.50 carbon dividend - $10 carbon tax = $49.50). This net benefit will help low-income people to pay for higher costs of fossil fuels (due to carbon taxes) without falling further into poverty, and thus help prevent political backlash against the carbon tax. Even though it doesn’t cause any net tax burden, the carbon tax will make all use of fossil fuels more expensive and speed up the transition to renewable energy. The higher the carbon tax, the faster the transition will be.

This carbon dividend policy is not invented by Boyce; he has just written the first book devoted to it. In fact, carbon dividends are the policy advocated by Citizens’ Climate Lobby (www.citizensclimatelobby.org) a worldwide group of volunteers dedicated to educating the public and politicians about how to stop climate breakdown by implementing carbon taxes and dividends. The imposition of a carbon tax and dividend policy in Canada at the beginning of 2019 was largely the outcome of years lobbying by this group. This initial success in Canada needs to be replicated in every country if climate breakdown is to be prevented. Since Bangladesh is one of the countries most vulnerable to climate change, and there is now a large expatriate Bangladeshi population around the globe, one hopes that Bangladeshis wherever they are will join the campaign to stop global warming through carbon taxes and dividends.

Climate Changed: A graphic novel by Philippe Squarzoni

This article was published in Dhaka Tribune on February 9th, 2019.

French cartoonist Philippe Squarzoni has taken on the huge task of trying to convey the complex science of climate science and the global emergency that it implies in the form of his autobiographical/documentary graphic novel, Climate Changed. Hopefully this will enable the general public, which does not always seem inclined to wade through dense texts on scientific topics, to get a better appreciation of the challenges of global warming.
The book starts with the author contemplating the difficulties of tackling the subject of global warming in comic book form; unlike most comic book stories, it’s a scientific phenomenon without the conventional beginning and end of most stories. His solution is to place a fairly detailed exposition of climate science in the context of an autobiography. The end result is illuminating. It serves to remind the reader that climate change is not just happening to the globe. It’s happening to all of us, since we all live on this planet that is rapidly heating up, and is already presenting us with real consequences in the form of record high temperatures, droughts and deadlier storms. His visit to his childhood home and his observation of how much smaller and how different it seems as an adult illustrates that the comfortable planet we knew even a few decades ago is gone forever; the climate has changed, and it’s a now a new, more dangerous world that we live in.
As a low-lying country which is both densely populated and incredibly vulnerable to sea level rise, Bangladesh gets two mentions in the book. Squarzoni quotes climatologist and World Bank economist Stephane Hallegatte: with ‘a rise in sea level of a little over 3 feet (1 metre)… numerous densely populated coastal regions such as the Ganges and Nile deltas could be flooded. Millions of people will be driven out, and agricultural production will be severely affected. 20% of Bangladesh could be flooded.’ Bangladesh comes up again when Hallegatte discusses the potential effect of millions of climate refugees on the international arena: ‘If 20 million people leave Bangladesh and head for India, what do we do?… What will the India and Bangladesh of 2060 be like? Will tensions between them have eased? Or will they be at war?’. Even in Bangladesh, such long-terms concerns are rarely addressed in the short-term new cycle.
Unfortunately, the effects of climate change will be felt disproportionately by the poor; this is made clear by Squarzoni’s account of the severe flooding caused by Hurricane Katrina hitting New Orleans in 2005. The wealthier sections of the populace all evacuated upon hearing storm warnings a day in advance. The poor had no means to escape, and had to survive for days on the roofs of their submerged houses with most of the city being flooded with up to 23 feet of water. 30,000 people took shelter above the flood waters in the city stadium, until being finally evacuated by the government to the surrounding states. Desperate people started looting shops for supplies, with the result that a curfew was imposed; US soldiers freshly returned from Iraq were called in with orders from the state governor to shoot to kill. Total deaths numbered 1293, and 2 million were displaced; hundreds of thousands for over a year. Immense numbers were left in financial ruin with no means of rebuilding their ruined homes. All this in the richest country in the world. The question arises as to how poorer countries would deal with similar storms and floods, which will grow more common everywhere as global warming adds heat and power to storm systems. Will wealthy countries treat poor countries any better than they treat the poorest of their own citizens?
‘So, how to end this book?’ Squarzoni asks as he draws to a close. He observes that so far humanity has failed to deal with the existential threat of climate change by curbing fossil fuel use, and thus nearly closes on a pessimistic note; but as he says, ‘The story isn't over’. Everything depends on how successfully we the public are able to lobby governments of the world to act over the next decade (which according to the 2018 International Panel on Climate Change report is all the time we have left to make severe cuts to fossil fuel use and thus prevent catastrophic climate change of over 1.5C).

Monday, 23 January 2017

How 'Merchants of Doubt' convinced the US to ignore climate change

In 1988, Dr. James Hansen, senior climate scientist at NASA, testified to the US Senate that global warming caused by burning fossil fuels was a serious threat. Yet for 28 years the world did practically nothing, and both greenhouse gas emissions and global warming continued. Global inactivity was largely due to successive US governments pretending that the science of global warming was still uncertain and not worth the expense of reducing coal, oil and gas use. The willful ignorance of climate science on the part of the American politicians was encouraged by a small group of right-wing scientists who were not specialists in climate change, but were rather driven by ideological opposition to the increased government regulation that would obviously be required to tackle issues such as global warming. Reluctance of US authorities to consider reducing fossil fuel use resulted in all other countries refusing to to act as well. How this happened is the subject of Merchants of Doubt: How a handful of scientists obscured the truth on issues from tobacco smoke to global warming, by Naomi Oreskes and Erik Conway.

Oreskes, a professor of history of science at Harvard University, points out that a number of the prominent scientific advisors of the US government (recurring names are Fred Seitz, Fred Singer, Robert Jastrow and Bill Nierenberg) started their careers in nuclear weapons and missile research in the midst of Cold War conflicts with Russia. Thus these scientists were reflexively anti-Communist and inclined to oppose any scientific research that made a case for more government regulation; they saw such regulations as a sign of the socialism which they had opposed all their careers growing within the US. Hence this small but influential group of senior scientific advisors continuously opposed emerging scientific findings that tobacco caused cancer, that industrial pollution caused acid rain, and finally that dangerous climate change would be caused by burning coal, oil and gas. Unfortunately, these anti-regulation/pro-market scientists found support in the fossil fuel industry, various pro-market media and think tanks, and various US politicians whose political campaigns received money from coal/oil/gas companies. The result was that the science of global warming and climate change was perceived by the media, the government and the public as contested for decades after a scientific consensus on these issues was in fact established. Due to these manufactured doubts, government policy was slow to accept the scientific evidence on the danger of man-made global warming.

Of the various scientific issues discussed by Oreskes, climate change has by far the biggest impact on humanity as a whole and thus also created the most resistance amongst anti-regulation scientists, corporate lobby groups and politicians. Reading Oreskes' book, one sees how na├»ve it is to expect that worldwide government policies regarding global warming would be simply be decided based on scientific evidence. The fact is that the political systems which have been established to govern democratic countries are not set up to make decisions based on science. Rather they are set up to encourage politicians to make decisions based on the likelihood of winning the next election. Multinational coal, oil and gas companies have more than enough money to make political donations big enough to legally “buy” political support for their industries in spite of dire scientific warnings. The public has largely been deceived by fake science produced by non-specialists in climate change presenting themselves as 'experts' and muddying up the waters with doubt.

The past 30 years has shown that voters around the world, and especially in the US, have not been sufficiently informed of the dangers of catastrophic global warming which could cause worldwide water shortage, crop failures and famines resulting in hundreds of millions of deaths if left unchecked. Fossil fuel companies and anti-regulation scientists and politicians have taken advantage of the lack of knowledge of climate science among the public to deceive and endanger us all. Hopefully this will change as the media and the public wake up to the threat of global warming. Otherwise the world will continue getting hotter, and our children might grow up to inherit a climate running amok.

Copyright 2016 by Zeeshan Hasan. First published in Bangladesh on June 1, 2016 in Dhaka Tribune.

Wednesday, 22 April 2015

Global warming may cause "Climate Wars"

“Climate Wars: The Fight For Survival As The World Heats Up” by Gwynne Dyer investigates the worst case scenarios of global warming, via studies done by and interviews of risk-assessment professionals at the Pentagon and defense-related think tanks. Unfortunately, it does not make for reassuring reading. As the world heats up, the tropical and sub-tropical regions of Asia, Africa, Central America and South America are likely to become hotter and more arid; this is likely to decrease agricultural productivity and food production in these densely populated regions. The outcome could be a new age of warfare.
One possible location for conflict identified by Dyer is South Asia. Many of Pakistan’s rivers are reliant on sources in the Indian Himalayas. Due to global warming, the overall climate of the region is likely to become more dry and arid. This could spark increasing tension between India and Pakistan over the water in their shared rivers, possibly ultimately resulting in warfare between these two nuclear-armed states. This analysis also holds true for India and Bangladesh; however, since Bangladesh is not a nuclear power, the prospect of meaningful warfare between these two countries is not seen as a realistic or large threat by Pentagon planners, and not discussed in Dyer’s book.
As frightening as the possibility of an India-Pakistan war is the possibility of a Russia-China war. China is likely to become hotter and drier as global warming progresses. This is likely to affect water availability and agriculture, a major concern for a country of over a billion people. This may fuel expansionism on the part of China with the goal of controlling more land for food production. Any such expansionism might result in warfare with Russia, the dominant power among the ex-Soviet republics in the region.
These concerns seem remote in today’s world, where the worst case scenario for a bad crop in any country is increased food imports. However, the worst case scenarios of global warming inevitably involve a hotter, drier globe with less productive agriculture closer to the equator. In this scenario, it is not clear where the required shortfall in food will be produced, and whether there will be enough to go around. It seems that we may be living in an age of plenty which will be cut short by climate change. Life on a warmed globe means an age of scarcity, and increased risks of conflict.
By far the best outcome for everyone would be if governments around the world prevented global warming by real measures to cut carbon dioxide emissions. This requires taxes on fossil fuel use, and reinvesting the tax proceeds in renewable energy such as solar and wind power. Unfortunately, the governments of the world are still dragging their feet rather than taking real action. Further delay could well doom us to a future of climate warfare.
Copyright 2015 by Zeeshan Hasan. First published in Bangladesh on February 16, 2015 in the Dhaka Tribune.

Saturday, 29 November 2014

The real threat of global warming

by Zeeshan Hasan

Many people have a false perception of an ongoing 'debate' regarding the dangers of global warming and climate change. In particular, elected politicians intent on avoiding unpopular carbon taxes and higher fuel prices continue to assert that the relevant scientific issues are doubtful. Unfortunately, until now the non-scientist public has been deceived by a large number of books and newspaper articles by misinformed 'skeptics' of climate science who themselves have no understanding of the science involved. Fortunately, a glimpse into the real world of climate science is available through Global Warming: Understanding The Forecast by David Archer, an ocean chemistry professor at the University of Chicago. Archer's book is an introductory climate science text which aims to make the basics of climate science comprehensible to any one with a high school background in science.

The basic science of how carbon dioxide emissions raise global temperatures is outlined by Archer. On the one hand, the earth is constantly being heated by sunlight. On the other hand, the Earth is also cooled by loss of heat into space as infrared radiation. These two continuous mechanisms of heat gain and heat loss by the Earth result in a thermal equilibrium at the average global temperatures which we experience.

Heat gain from the sun is relatively constant, varying only slowly over time; however, heat loss into space has been reduced significantly by humans over the last century. Atmospheric 'greenhouse gases' such as carbon dioxide have the property of absorbing the infrared radiation which carries heat from the earth into space, and thus reduce the cooling of the earth. This effect of carbon dioxide is called the Greenhouse effect; it was discovered over a century ago and is undisputed. Since the Industrial Revolution, humans have been continuously burning fossil fuels such as coal, oil and gas, and thus adding huge amounts of carbon dioxide to the atmosphere. This has resulted in an increase of the carbon dioxide concentration in the atmosphere from 320 parts per million in 1960 to about 400 parts per million today, or about 20%. This additional carbon dioxide functions like a blanket or greenhouse around the planet, slowing down loss of heat into space. If the same amount of solar heat comes into the Earth, while simultaneously heat loss from the Earth to space is reduced by additional carbon dioxide, then the Earth has to get warmer. At a higher temperature the Earth's heat loss by radiation into space increases, because hotter objects lose more heat through infrared radiation than cooler ones; and the planet once more reaches a stable temperature.

A good analogy to the above is a pot of food simmering on an oven above a low flame; putting the lid on the pot does not change heat gain from the oven, but reduces heat loss through evaporation from the open pot and thus makes the food cook at a higher temperature. Our carbon dioxide emissions are effectively putting a lid on the earth, making heat from the sun 'cook' the planet at a higher temperature.

The question is whether a hotter stable temperature of the globe would be one capable of sustaining human life as we know it. Climate scientists have evidence from ancient ocean sediments that increasing the level of greenhouses gases in the atmosphere can cause temperatures to rise. Such an event took place 55 million years ago, when thousands of billions of tons of greenhouses gases were released into the atmosphere (probably because of a peak in volcanic activity). This event is known as the Permian Eocene Thermal Maximum (PETM). During the PETM, global average temperature rose by about 5 degrees C and 90% of life on the planet perished. Such an increase in global average temperature today would have terrible consequences, rendering much of tropical and sub-tropical Asia, Africa, central America and southern Europe too hot and dry for agriculture. The consequences would be famine on a scale never seen before, and billions of deaths.

Dangerous global heating events like the PETM may seem distant and irrelevant. But as a comparison, burning all world's known reserves of coal would release about 5000 billion tons of carbon dioxide, comparable to the surge in greenhouse gases which caused the PETM. Our current course is to exploit not only existing coal reserves but also oil and gas. So it is entirely within our power to destroy our planet.

Continuing our current policies of exploiting all fossil fuels available will literally ensure the end of the Earth as we know it. The only way to stop it is to keep fossil fuels in the ground and switch to solar, wind or nuclear power, none of which emit carbon dioxide. This will require worldwide imposition of carbon taxes to raise fuel prices and make investment in alternative energy feasible. The leaders of all countries need to make some hard decisions, which they have failed to do in 20 years of climate negotiations. They will only do so now if the public demands it of them. The public needs to make their voices heard.

 (Printed in Bangladesh on Nov. 30, 2014 by the Dhaka Tribune.)

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)