Climate changes = more hurricanes? Simple maths or false numbers?

In last week’s article on Hurricane Sandy I stated out and out that the storm’s strength and northerly track were mainly the effects of climate change. Scientifically such a black and white statement should probably have been supported with evidence and as such I have decided to review a recent paper from the journal Nature Geoscience on the links between climate change and tropical cyclones. Hopefully this will serve to support the stance I made in the previous article and inform readers who wish to explore some of the scientific evidence of a link between climate and the intensity of hurricanes. Is it a simple relationship or a more complex one?

The paper, titled ‘Topical Cyclones and Climate Change’ and authored by Knutson et al, analyses both the past correlation between climate change and tropical storm characteristics and uses data from modelling to project the effect of climate change on tropical cyclone intensity in the future. Sea surface temperature (SST) has been tracked and found to have increased by several tenths of a degree over the last few decades. The paper cites the IPCC fourth report and US Climate Change Science program report 3.3 that states that these changes are ‘very likely’ due to anthropogenic global warming.

When considering past data the picture painted by the study is confused. While the rise in SST is easy to follow how this has effected Tropical Cyclone strength is less certain due to both the suggestion of natural climatic variability in the Atlantic (relevant for Atlantic tropical cyclone frequency) and a number of biases in the data especially as data is more readily available and reliable for the Atlantic Ocean compared to the Pacific. The paper states that without adjustment for possible missing data hurricanes have increased in frequency from the late 1800s onwards but shows no significant trend from the 1850s to the present. In terms of intensity (measured via the power dissipation index or PDI) it is also difficult to find an overall trend. The paper compiles information from a number of studies as the graphs below show until very recently there has been no rise in PDI over a prolonged period but rather a number of short term peaks and troughs with no significant long term trend.

However when it comes to the projection of future intensity and frequency of tropical storms (and therefore hurricanes) the paper presents more defined conclusions. It is projected that frequency of tropical cyclones will either remain the same or reduce on a global scale as greenhouse warming continues. The decrease may be as much as -34% although in some individual basins there is an error factor of +/-50% on these projections. In terms of intensity the maximum wind speed is predicted to rise (on average) by +2 to 11% while rainfall is modelled to increase by +20% within a 100km radius of the cyclone centre. There is an error margin of +/-15% associated with some of the methods of modelling (usually for individual basins).

There is still a degree of uncertainty with these figures, especially the figures for cyclone frequency which the authors state they have ‘very low confidence in’. However the models have been calibrated against past observed data so at the very least the overall trends predicted by modelling can be relied upon.

This brief summary of the paper has attempted to highlight the relevant data and trends within the data. The conclusions that can be drawn from it are that it is likely that climate change will cause an increase in the intensity of tropical storms (and therefore hurricanes) but that it is not yet certain whether it will have the same effect on frequency. Despite this these conclusions provide a strong link between climate change and hurricanes.

The rising tide: climate change and borders

In March 2010 the minute uninhabited island of New Moore or South Talpatti vanished. Where the year before there had been a small flat island that never rose more than two meters above the sea there was now only open water.

 At the time the media was a little sensationalist. It was cited as an example, possibly the first, of a whole island being lost to the rising seas of the climate change era. In fact it was, according to Indian academic Sugata Hazra a combination of rising seas, increased monsoonal rain than had in turn increased erosion and subsidence than had combined to pull New Moore/South Talpatti below the waves. Climate change played the decisive role but it wasn’t as if the Indian Ocean jumped by two meters overnight.

 The island has been given two names above for a particular reason. It is, or was, claimed by two nations. To the Indian government, who raised their flag on it in 1981, it was New Moore. To the authorities in Bangladesh it was South Talpatti. To both it was invaluable in staking a claimed to a treasure trove of oil and gas predicted to be held beneath the ocean floor around it. The fact that climate change effectively ended this dispute and further complicated the rights to exploit any potential natural resources in the region is the most interesting aspect of the story of March 2010. The rising of the oceans driven by climate change is a scientific truth but the way this will change the very boundaries of the world and shape the politics of ownership is much less explored.

This was discussed earlier in the week in an article in The Diplomat concerning the myriad of small islands in the South China Sea often claimed by three or four separate countries. A more complex version of the situation in the Indian Ocean the territorial waters, rights for exploitation and fisheries and the history of seven different nations are tied up in various disputes over islands. It is a fairly commonly help belief among defence analysts that the increasingly tense stand offs over these islands, especially between China and Japan and North and South Korean may be the most likely cause of war in South East Asia in the immediate future. However as the article points out, some of the islands in question are so low lying they are submerged during typhoons. Those that aren’t are still only a few meters above sea level at the most and are some of the places in the world most vulnerable to sea level rises. While national pride and vast amounts of money may be at steak when claim to islands are made they may have been drowned before disputes can be resolved.

One of the islands in the Spratly Islands archipelago. Claimed by five different nations nowhere on the archipelago is higher than 4m above the sea.

 A separate issue is the loss of land already inhabited. Major sea level rise over the next century is predicted to destroy huge areas of coastal Bangladesh, reducing the size of the country drastically. More pressing than that is the potential for whole inhabited islands to vanish. Scores of tropical atolls such as Piul Island in Papua New Guinea are being washed away and year after year their inhabitants can do nothing but watch as their land noticeably shrinks. The concept of boarders and boundaries may be intrinsically human but in these cases nature is beginning to decide where countries begin and end, or even if they exist at all.

Fun Things of a Friday

It was the anniversary of this event a few weeks back, so lets relive Michael Fish getting it very very wrong all over again...

Executive Order 13514

Executive Order 13514 is one of the reasons people in the environmental movement should be very happy that Barack Obama was re-elected as US president this week. Looking through the election campaign of each major candidate you will see little in the way of solid environmental policy. However it was the signing of Order 13514 back in 2009 that marked Obama out as the 'environmental' candidate.

An executive order is a direct instruction issued by the President to US federal agencies that does not (usually) have to be approved by congress. In this case President Obama ordered all arms of the US government to adapt and 'prepare' for climate change. This may sound a bit woolly but it has in fact been highly effective. It requires all government departments to set a greenhouse gas reduction target for 2020, reduce waste and pollution and promote 'environmentally friendly' technology. Its true value however is in the long term planning aspect of the order. Departments must appoint a climate change specialist to oversee the planning and implementation a climate adaption strategy so that the agency will be able to continue its functions as climate change effects the US.

While at first glance the order may seem vague it has nevertheless been taken seriously by the branches of the government it effects. For example part of the military’s adaptation plan has resulted in a survey of all American water resources and coastlines to assess their vulnerability to climate change and how best they can be protected. On a larger scale, all employees in the departments effected are to receive training on the basics of climate science.

All of these changes have resulted in a 'trickle down' of environmental awareness because not only do the agencies of the federal government have to apply Executive Order 13514, but all private sector contractors that work with the government will have to as well. While it is too early to tell how great an impact Executive Order 13514 will have on America’s fight against climate change it may well be an important early step in changing attitudes and therefore actions towards the environment.

(The order can be read in full here)

Hurricane Sandy, the smallest of silver linings in a sea of clouds?

New York’s Mayor Michael Bloomberg did a very brave thing last week. In the wake of Hurricane Sandy Bloomberg stood up and mentioned the C words while discussing the destruction brought to New York. ‘Our climate is changing’ he said ‘And while the increase in extreme weather we have experienced in New York City and around the world may or may not be the result of it, the risk that it might be -- given this week’s devastation -- should compel all elected leaders to take immediate action’. Despite the infuriating equivocation within these words it is still the one of the most direct statements a mainstream politician has given about climate change while still in office. Christmas has come early for the environmental movement.

The Hurricane itself has, it would seem, made climate change a campaign issue. It seems that more than the tragic human impacts of the storm, the politics of it have become a major talking point as the US election clock counts down to midnight. As Bloomberg also pointed out, Mitt Romney and Barak Obama both have green credentials but while Obama has put his money (and obvious legislative power) where his mouth is Romney has performed a spectacular U-turn. The man who brought in emission reducing laws as a state governor is now the presidential candidate infamous for his ‘I’m not here to slow the rise of the oceans’ sound bite. With huge areas of New York inundated with salt water his quip now seems a lot less clever.

 The scientific jury is still out on whether Sandy was ‘caused’ by climate change. Some climate scientists have insisted that New York was the victim of a ‘perfect storm’, with a number of natural phenomenon combining to create the storm. Others (such as the University of Texas Tech’s Katharine Hayhoe) have noted that while the storm may have had natural origins warmer sea surface temperatures and an arctic weather front both linked to climate change were major factors in Sandy’s intensity.

As I have stated before the lack of willingness in American politics has been a major roadblock to getting comprehensive global emissions agreements. Sandy was a real shock to the system, a major storm event by any standards but even more surprising in its northerly latitude and direction of movement. While on a scientific level there is not yet a conclusive link between climate change and ‘Superstorm Sandy’ it, at the very least, demonstrates the scale of storm we may soon have to deal with if climate continues to change. Sandy’s ‘silver lining’ will be if this demonstration pushes politicians and the public in general into action.

 Of course this may not happen. While the fact that climate change is being talked about in relation to Sandy is a positive step, the ability of governments and voters both to ignore the past when it comes to natural disasters has to be reckoned with. In the post-Katrina world of 2005 there were some who tried to use the hurricane as a catalyst to push new environmental policy. On paper the destruction of huge areas of a low lying coastal city, causing nearly 2,000 fatalities and over $100 billion of damage should at least have started a debate into whether rising sea levels and warming sea temperatures will make such events more common and what we should be doing to stop this. Seven years later another coastal city has suffered a similar fate with no such discussion having taken place. We must hope that this time the opposite happens and with America talking about climate change the rest of the world may follow suit.

Fun things on a Friday

I feel I don't need to say anything about this...

From dirty coal to nuclear bliss: What will the UK's switch to nuclear power mean in practice?

Since the announcement under the last government that the UK's energy future was to be tied to the double edged sword of nuclear power parties on all sides of the atomic energy debate have been kept in the lurch. False starts and u-turns have slowed progress to a stutter but now, as negotiations between the government and EDF enter their final stage and Hitachi sign a £700 million deal to build new reactors the likelihood of increased nuclear power is slowly becomes a reality. We need to ask, what will this mean?

 Nuclear power is an issue dominated by the ghosts of past disasters. Fukashima and Chernobyl weigh heavily on the public consciousness whenever nuclear power is debated. However putting aside the obvious safety concerns it can not be denied that nuclear energy is a clean and more serious alternative to fossil fuel combustion than any other proposed renewable fuel source. Not only is the technology already in place and well understood but the carbon emissions associated with generation compared to,for example, coal are significantly lower. The World Nuclear Association cited a 2002 study of the Forsmark plant in Sweden shows a 3.10 gram per kilo Watt hour carbon footprint. This figure is derived from the carbon emissions involved in the building of the plant, mining of ore for use in generation, transport, waste management and other factors. These energy 'inputs' are reckoned to represent only 1.74% of the total energy generated at an average plant during its lifetime. Nuclear power may be the only way for the UK to even come close to meeting its emission reduction targets.

For you, me and everyone else paying a electricity bill the effect of increased nuclear power is unclear. Some sources suggest that in the long term nuclear power will be cheaper than coal and gas, especially as fossil fuels become harder and harder to extract.

However initially there may be a hike in prices associated with the setup costs of a new generation of nuclear power plants. However the building of new nuclear power plants may, in the end, be surplus to requirements. A report in October of this year suggests that by 2018 the renewable sector will have outstripped nuclear power and that by as soon as 2015 10% of British homes will be supplied with power from renewable sources. Faced with this kind of competition and with progress on new nuclear infrastructure slow nuclear power may never live up to its billing as the 'clean' future of British power.