Tag Archives: carbon dioxide

Change is coming whether they like it or not

[This post is dedicated to the 100s of  MPs who  chose not to attend a debate in parliament on climate change in a week when the UK experienced its hottest ever winter’s day.]


Blizzards, strong winds, drifting snow, bitter cold – that was the story in early March last year when the “Beast from the East” collided with storm Emma bringing extreme weather and disruption to life across large parts of the UK.  Towards the end of June, by contrast, the sun began to shine and daytime temperatures climbed into the thirties and stayed that way across much of the country until August (the picture at the top of this post shows the effect of the long hot summer on the UK countryside).  Elsewhere across the globe, reports came in of flooding, wildfires, severe tropical storms and unusually high and low temperatures.  Many of these weather extremes can be attributed to climate change and there is considerable concern that the planet is heading for climate catastrophe.  David Attenborough expressed this fear at a climate change conference in Poland:  “If we don’t take action, the collapse of our civilisations and the extinction of much of the natural world is on the horizon.”


Heavy snow falling in early March while a great tit continues to feed


In the UK, it was the long, hot summer, the joint hottest on record, that made people think most about a changing climate.  The weather here is, of course, notoriously fickle and some will remember that in 1976, we experienced a similar long, hot, dry summer, so how can we disentangle normal weather variation from climate change?  One way of looking at this was shown by Simon Lee, a PhD student at the University of Reading, who shared graphs on Twitter of the global temperature anomalies in June 1976 and in June 2018 (see pictures below).  These show that in 1976 the UK was one of a few unusually hot spots in an otherwise cooler than average world whereas in 2018 much of the world, including the UK, was hotter than the average.   The 2018 picture shows climate change in action: the planet is warmer making heatwaves more likely.


The pictures show temperatures across the world in June 1976 (upper panel) and in June 2018 (lower panel) compared to the average across the period 1951-1980. Red and yellow mean higher, blue means lower. Kindly supplied by Simon Lee who generated the images from NASA/GISS data.

Careful measurements of the average surface temperature of the planet show that it is currently about 1oC hotter than in pre-industrial times.  This may not seem very much but it is enough to disturb the complex systems that create our weather.  As a result, heatwaves may be more frequent in summer and, in winter, polar air may be directed southwards bringing abnormal, freezing temperatures.  Also, a warmer atmosphere holds more moisture so that rain and snow may be more severe.  Climate breakdown might be an apt description of these changes.

This global heating is a result of human activity.  The emission of greenhouse gases, particularly carbon dioxide produced by burning fossil fuels such as coal, gas, oil and petrol, traps heat in the atmosphere so the temperature of the world increases.  We have known this for some time and we have also known that the solution is to reduce carbon emissions. Atmospheric levels of carbon dioxide have, however, continued to climb because no government has had the will to introduce the extreme lifestyle changes required to curb emissions.  Some governments, including our own, have even encouraged the continuing extraction of fossil fuels.

It is, therefore, significant that in October 2018, the Intergovernmental Panel on Climate Change (IPCC) issued a report containing a dire warning: we must make urgent and unprecedented changes to the way we live if we are to limit heating to 1.5oC above pre-industrial levels.  To achieve this target, we must reduce net global carbon emissions by 45% by 2030 and to zero by 2050 – fossil fuel use must be drastically reduced by the middle of the 21st century but we must start the reduction now.  Should we fail to achieve this 1.5oC target, the risks of drought, flooding, extreme heat, poverty and displacement of people leading to wars will increase significantly.  The world will no longer be the place we know and love and parts of it will become uninhabitable for humans and the rest of nature.

How do we achieve this reduction in carbon emissions? Voluntary measures such as suggesting people fly or drive less will not work.  The only way this reduction can be achieved is through coordinated government action based on recommendations made in the IPCC report.  These include the planting of more forests and the chemical capture of carbon dioxide to reduce atmospheric levels of carbon dioxide.  There must also be a drastic shift in energy production and in transport away from fossil fuels and this can be driven in part by investment and subsidies directed towards clean technologies.  A carbon tax can also help drive this shift but the tax will need to be high enough to force change, for example by taxing energy companies who burn fossil fuels so that they invest in cleaner technologies.  In the short term, costs to consumers may rise, so politicians would need to keep the public on side, for example, through tax incentives.  If we grasp the opportunity, the scale of change may have the unexpected bonus of allowing us to design more sustainable and equitable societies.

The IPCC report set out very clearly the changes required to avoid damaging global climate change so there was great anticipation when the UN Climate Change Conference convened in Katowice in Poland just before Christmas.  Astonishingly, given the gravity of the situation, the 200 countries represented there failed to agree new ambitious targets for greater reductions in carbon emissions. Four countries (USA, Saudi Arabia, Russia and Kuwait) would not even sign a document welcoming the IPCC report; these countries are of course all oil producers.

It was at this conference that David Attenborough issued his warning about the collapse of civilisations but there was another hugely impressive intervention.  This came from 15-year old activist Greta Thunberg from Sweden.  She had already achieved some notoriety through her weekly climate strikes where she missed one day of school to protest about climate change.  Her actions have stimulated many thousands of young people around the world to do likewise.  Thunberg also spoke in London at the launch of the new grass-roots movement, Extinction Rebellion, which intends to use peaceful protest to force governments to protect the climate.  These new trends offer some hope for the future since it is the young of today that will bear the climate of tomorrow.

Greta Thunberg, 2018 (cropped)
Greta Thunberg

Here is part of Greta Thunberg’s speech given at the Katowice conference:

“For 25 years countless people have come to the UN climate conferences begging our world leaders to stop emissions and clearly that has not worked as emissions are continuing to rise. So, I will not beg the world leaders to care for our future, I will instead let them know change is coming whether they like it or not.”

“Since our leaders are behaving like children, we will have to take the responsibility they should have taken long ago. We have to understand what the older generation has dealt to us, what mess they have created that we have to clean up and live with. We have to make our voices heard.”

I am grateful to Simon Lee for generously supplying the temperature anomaly graphs.

This article was published in the March 2019 edition of the Marshwood Vale Magazine.

For global warming please read global weirding – how climate change is affecting our lives

Here is an article I wrote for the April edition of the Marshwood Vale Magazine.

South Devon Railway sea wall breach February 2014
Storm damage at Dawlish in South Devon where the sea wall and railway line were destroyed

This winter, the UK experienced an exceptional series of storms. Heavy rain combined with strong winds and high waves lead to widespread coastal flooding and coastal damage. There was significant disruption to individuals, businesses and infrastructure and many parts of the country were affected. Transport was badly hit including the destruction of the main railway line into the south west at Dawlish.

This was indeed extreme weather and we now know that in England and Wales this was the wettest winter for almost 250 years. We are not alone, however, in experiencing extreme weather. The eastern side of the US and Canada was unusually cold this winter whereas California suffered a severe drought. Australia and Argentina experienced exceptionally high temperatures whereas Brazil received record rainfall.

The extreme weather has had the interesting effect of finally making politicians speak up about climate change. Here is what David Cameron said recently: “I believe man-made climate change is one of the most serious threats that this country and this world faces.” John Kerry went a step further, placing climate change alongside disease, terrorism, poverty and weapons of mass destruction as global threats.

But before we get carried away by band-wagon jumping politicians, let’s think about what is really going on. What we have been experiencing recently in the UK is extreme weather. Climate change, however, refers to long term changes in weather patterns. The UK weather is notoriously unpredictable so is there really any evidence for changes in weather patterns that would indicate a change in our climate?

A study of UK weather over the last 140 years found evidence for an increase in the intensity of winter storms hitting the southern part of the country. Instances of heavy rain have also increased in frequency, consistent with a warming planet where a warmer atmosphere holds more moisture. Additionally, global warming has caused sea levels to rise by about 12 cm during the 20th century exacerbating the effects of storms at the coast. The climate in the UK is indeed changing and the recent extreme weather is part of this.

If the climate is changing then we come to the biggest and the most contentious question: why is it changing? Here we need to look at a bit of climate science. The earth is warmed by energy from the sun and as the planet heats up it radiates heat outwards. Some of this heat is retained by so-called greenhouse gases, for example water vapour, carbon dioxide, methane in the earth’s atmosphere. As a result the temperature of the earth is maintained at a level compatible with human life. This is the way it had been for many thousands of years, in fact until the industrial revolution. Since the industrial revolution, however, humans have been increasing carbon dioxide levels in the atmosphere, principally in two ways: by burning fossil fuels (those laid down many years ago from decaying plants and animals) and by cutting down forests (reducing carbon dioxide removal by trees). Increased levels of carbon dioxide mean greater heat retention and the earth’s surface temperature is now nearly one degree centigrade warmer. This may not seem very much but there is also a huge reservoir of heat accumulating in the oceans. Taken together these are the processes described as global warming.

It doesn’t stop there: increased warming leads to disturbances in weather patterns. Higher sea temperatures cause melting of ice so that sea levels rise and the effects of storm surges are greater. Reduction in the size and thickness of the Arctic ice cap is also thought by some to lead to changing weather patterns in Europe. Warmer oceans mean that when storms and hurricanes occur they are stronger. A warmer atmosphere holds more moisture so that when a storm arises the rainfall is more intense. An example of these effects is provided by Typhoon Haiyan which killed at least 6000 people in the Philippines in 2013. Haiyan was the strongest tropical cyclone ever to make landfall anywhere in the world and was fuelled by warm water in the Pacific. Weather patterns are shifting and rather than talking about global warming we could speak of global weirding; in the end, however, it all comes down to climate change.

The implications of these observations for human life have led to intense debate about how much of the change in climate can be attributed to human activity. Among climate scientists, there is a strong consensus that climate change is a result of human activity (burning fossil fuels and deforestation). Last year a report from the Intergovernmental Panel on Climate Change recognised the shift in patterns of extreme weather since 1950 and concluded that most of the rise in global temperature since the mid 20th century was due to human activity. They also warned that without substantial and sustained reductions in greenhouse gases, there will be further warming and damaging climate change.

The message could hardly be clearer. Human activity is causing climate change. The sort of extreme weather we have experienced lately will recur. Things can only get worse if we sit on our hands and do nothing as we have been doing so far.

We, therefore, need to reduce carbon dioxide emissions and this means leaving fossil fuels in the ground rather than burning them. We urgently need a second industrial revolution that embraces and implements low carbon technologies. Governments must stimulate investment in these technologies and politicians must show vision and leadership.

Since I wrote this article, the Intergovernmental Panel on Climate Change has issued a new report showing that climate change is already affecting life in many parts of the world and may threaten food supplies in the future.

Climate change – more uncertainty or better presentation?


What do the following have in common?  Driving our cars, flying in a plane or using electricity made by burning coal or gas.  They all consume fossil fuels and they all put extra carbon dioxide in to the atmosphere.  The carbon dioxide is a “greenhouse gas” and there is broad agreement among scientists that increases in atmospheric carbon dioxide levels have driven an increase of just under one degree in global temperature during the last century.  There is also broad agreement that if we continue with our cars, planes and electricity the way we are, this will lead to further increases in global temperature coupled with climate instability.  These will lead in time to major effects on human lifestyle.

File:GISS temperature 2000-09 lrg.png
How the planet has warmed over the past 50 years

We rely on climate models to predict the extent of future change in global temperature.  These models are complex computer simulations that try to take account of as many of the variables affecting the climate as possible.  They are, however, only models and their predictions are affected by the uncertainty of some of the information used.  For example, a key variable is the amount of carbon dioxide that will be produced in the future and this is difficult to predict with accuracy, especially with the current economic upheavals. 

A problem is now emerging with the climate models which may provide new ammunition for the climate change-deniers.  The models are becoming ever more sophisticated, which sounds good, but according to Mark Maslin and Patrick Austin, writing in last week’s Nature (“Climate models at their limit”) the new more sophisticated models may contain greater uncertainty in their predictions.   This seems to be because the models now include a wider range of influences on the climate.  If there is uncertainty in each of these influences then there will be even more uncertainty in the outcome.   This does not mean the models are worthless.  The models are still able to predict future climate change; it’s just that there is a bit more wobble on the predictions.

Maslin and Austin are concerned that “To the public and to policy makers, this will look as though the scientific understanding of climate change is become less, rather than more, clear.”   

They continue: “Scientists need to decide how to explain this effect.  Above all, the public and policy makers need to be made to understand that climate models may have reached their limit.  They must stop waiting for further certainty or persuasion and simply act.”

Maslin and Austin propose a subtle change in presentation of modelling data and call this the “when” not “if” approach.  They suggest placing the uncertainty of predictions on the date by which things will happen rather than onto whether they will happen at all.   

Let’s restate this to emphasise this important conclusion:  we know that climate change is occurring and will get worse but we cannot be sure about the precise time scale.

Somehow also we need to unblock the political process whereby so little is being done about the problem of global warming.  As Maslin and Austin put it “Politicians use public opinion and scientific uncertainty as excuses for inaction.  They used to say “we need to wait until scientists prove that mankind is causing climate change”.  That hurdle has, arguably, passed, so now they have moved on to “we need to wait until scientists can tell us exactly what will happen and what the costs are” or “we need to wait for public opinion to be behind action””. 

The reality is that scientists have already provided enough information showing that something needs to be done to halt climate change.  All countries now need to set carbon reduction targets.  These do not need to be the same for all countries and may reflect different local circumstances but unless we move to carbon reduction there will at some point be severe consequences for the planet.

Climate change rhetoric versus climate change action

Leo blog : The Heartland Institute conference billboard in Chicago

Last week a billboard appeared over an Expressway in Illinois showing a picture of Ted Kaczynski, the Unabomber who was convicted in 1996 of a 17 year mail bombing campaign that killed three people and injured many more.  The caption read “I still believe in global warming.  Do you?”  The next day it had been removed.  The billboard was the work of the US climate-sceptic think-tank, the Heartland Institute.  There has been general condemnation of the billboard campaign and although Heartland may have received some publicity from the event, it seems likely that such a shoddy idea will have discredited the organisation in many people’s minds.   It also suggests a level of desperation on the part of the climate-sceptics.

The rhetoric has been heating up on the pro-climate change side as well.  Jim Hansen, who some describe as “the grandfather of climate change”, recently delivered the Edinburgh Medal Lecture at the Edinburgh International Science Festival.   According to Hansen, by not dealing effectively with the known issues surrounding climate change we are storing up expensive and destructive consequences for society in the future and this is an “injustice of one generation to others”.   He went on to argue that averting the worst consequences of human-induced climate change is a great moral issue on a par with slavery. 

These are strong words from both sides of the argument but perhaps this is no bad thing as it exposes the issues more clearly.  So, how do we find our way through this minefield of argument and counter-argument on climate change?   In trying to understand the background to the topic, I tend to be guided by the scientists who have been in the field for a long time and know the subject well.  Hansen is obviously one of those scientists and he and others have a paper coming out in Proceedings of the National Academy of Sciences USA where they lay out the issues and suggest solutions.  The paper is entitled “Scientific case for avoiding climate change to protect young people and nature” and can be read here.  There is a good discussion of how carbon dioxide emissions from burning of fossil fuels drive climate change and how far we need to cut emissions to stabilise the climate.  The take-home message is simple;  we need to cut carbon dioxide emissions to avoid damaging climate change in the future and the best way to do this is via a carbon tax coupled with extensive reforestation plans. 

There is also a very strong moral overtone to the paper and I want to quote a section relating to lack of action on climate change: “It is a matter of morality – a matter of intergenerational justice.  As with the earlier great moral issue of slavery, an injustice done by one race of humans to another, so the injustice of one generation to all those to come must stir the public’s conscience to the point of action”.

Perhaps you might feel that Hansen is too close to one side of the argument?  Where do you then look for guidance?  One possibility is the Royal Society, the premier scientific body in the UK, who should know what they are talking about.  In 2010 the Royal Society produced a report: “Climate change: a summary of the science”.  The report concluded that there was indeed warming of the planet and that human activity (burning of fossil fuels and changes in land use) was the major cause of the warming over the past 50 years.  Continuing increases in atmospheric carbon dioxide caused by continuing use of fossil fuels would lead to further warming of the planet.  The report is very cautious in its conclusions but it agrees with Hansen’s ideas.  If you want a more detailed discussion of the levels of carbon dioxide desirable for climate stability and the need to reduce emissions, have a look at 350.org and Skeptical Science.

It doesn’t feel to me like there is much argument.  Climate change driven by carbon dioxide emissions from burning of fossil fuels is happening and needs to be stopped for the future of the planet.  We know this now and yet we are not doing enough to prevent climate change.  It doesn’t really matter whether you dress it up as a moral issue or not but if we don’t get on and do something soon, history and our grandchildren will judge us very badly.