2016

With 2016 drawing to a close the media has been full of reflections on what a year it's been. A notable omission from many of these articles has been how this year has seen climate change progress at a record breaking rate. However, I did come across this article which has a few of the biggest changes and milestones we saw this year. It's well referenced too, so a useful tool if anyone tries to tell you things aren't all that bad/ climate change isn't happening. Check it out here!

Extreme weather

Climate change often receives the most attention in the media when extreme weather is in the news. It seems that every hurricane, flood,  or heat wave sparks a new round of headlines. The public seem to respond to this effect; a 2014 study found that following personal experience of Hurricanes Sandy and Irene, students in the north-east of the US showed increased concern about climate change. Previous negative attitudes towards ‘green’ politicians were even reversed.

However, it’s less certain that these links are scientifically accurate. Is climate change actually causing the rate of extreme weather events to increase?

Over the last few years a number of papers have been published in which the links between specific extreme weather events and climate change have been investigated. However, not much has changed in the way these events are reported in the news. This week a report was published discussing the both the science of extreme weather events and, perhaps even more interestingly, how this is communicated.

Contrary to my impression, the report found that even when links were well established, extreme weather events were often discussed without any mention of climate change- particularly in the US. However, it did note that climate change reporting is dominated by extreme weather events. This is doubly concerning, highlighting how under-reported climate change impacts are. The report also found that prominent public figures played a large role in influencing public opinion, even if they were unqualified to comment

In light of this, the report makes some recommendations about how to best communicate scientific understanding of climate change. The main points are that the reporting should focus on what we do know, rather than what we don’t, and that pessimism and despair should be avoided as they tend to prompt inaction.  This advice may seem common sense, but in reality is rarely followed for a number of reasons. For example, talk of ‘uncertainty’ and ‘error’ is common in science, but these words have subtly different meanings in everyday usage that tend to confuse the public.

This advice could be applied to many areas of science, but is particularly useful for climate change where public understanding and concern lags far behind the science. Let’s hope that these recommendations are widely read and followed, and that it’s enough to counteract the new wave of ‘sceptics’ coming into power in 2017.  

Greenwashing

Rather than look at an article this week, I thought I would be interesting to talk about adverts. This was prompted by the Shell #makethefuture campaign currently running. Its main adverts feature a number of celebrities and cute cartoons of multiple renewable energy projects Shell are currently involved in.

When I first saw the adverts, I was pretty impressed. Burning fossil fuels is the single biggest contributor to the greenhouse gas emissions causing climate change. We need investment in renewable energies to allow us to transition away from fossil fuels without corresponding reductions in quality of life. Furthermore, many of the projects featured can be used in areas without an extensive or reliable energy infrastructure, and so potentially could play a huge role in aiding access to electricity in these areas.

However, a little research has made me somewhat more sceptical about these adverts. They’re not advertising a specific product or service, but are instead a PR exercise aiming to improve the brand’s image in the public eye. In fact, it’s a classic example of what has come to be called ‘greenwashing’: a PR technique used to paint a company as environmentally friendly despite its activities being anything but.  

So what led me to these conclusions? A quick look at some figures is pretty revealing. In 2016 Shell created a ‘New Energies’ division to invest in renewables. Great! Except that this branch of the business receives investments less than 1% the size of Shell’s investments in extracting fossil fuels. That’s an annual expenditure of £200milllion vs the £30 billion spent on oil and gas extraction.

Shell doesn’t have a good record on this front. In 2009 it was reported that despite running adverts mere months before promoting its green credentials, Shell had withdrawn funding for most renewables due to their lack of profitability. In 2008 Shell was reprimanded by the UK Advertising Standards Authority for a ‘misleading’ advert in which it appeared to label its exploitation of the Alberta Tar Sands and the development of the largest oil refinery in the USA as ‘sustainable’.

Figure 1: Shell's 2008 advert deemed 'misleading' by the UKASA.

It’s worth pointing out of course that Shell is FAR from the only offender in this area. See also BP (formally British Petroleum) rebranding itself ‘Beyond Petroleum’ and ExxonMobil running adverts about how green it is while funding climate change denial on a grand scale.

The fact is, these companies’ profits and viability depend on extracting and burning fossil fuels. That’s how they’ve always made their money, and that’s how they hope to continue to make their money. Why not? They know how to do it and there are incomprehensible profits to be made.

The problem for us is that world cannot go on burning fossil fuels at this rate if we are to avoid catastrophic climate change. In fact, a 2015 paper in Nature estimated that in order to give us a chance of avoiding 2˚C warming, 80% of known coal reserves, 50% of known gas reserves and a third of known oil reserves cannot be burned. Carbon Tracker’s 2011 Unburnable Carbon Report introduced the idea of a ‘carbon bubble’: the fact that if any meaningful action is taken to avoid climate change, the assets on which these companies base their business models and financial reporting will become stranded. To put it another way, these companies can talk about renewables all they want, but as it stands their viability is reliant on us burning enough fossil fuels to cause climate change far far exceeding 2 ˚C.

So what can be done? Shareholder pressure is having some success, for example leading to ExxonMobil agreeing to stop funding climate change denial (not that they stuck to it).  Many fossil fuel divestment campaigns are also gaining traction , following the success of boycott movements in the past (if you’re interested, UCL has its own campaign).

I personally think that ultimately these companies are too large and too powerful to have to respond to anything but globally coordinated regulation by governments. And that’s unlikely to happen (in democracies at least) until the public demand it. And as long as the fossil fuel giants are keeping us happy with pretty films about how they’re going to change the world, we don’t seem that interested in demanding that our governments take bold action to keep fossil fuels in the ground. It may seem petty, but greenwashing is an incredibly powerful weapon in the arsenal of these companies. Don’t fall for it.

Visualising Global Change

Something a bit different this time, but an interesting perspective on how mass media can change our worldview nonetheless. This week Google Earth updated their Timelapse feature, and it’s really worth checking out (or have a look at the whole collection on youtube here). Not only are the compilations beautiful, they are also an excellent way to visualise the effects we’re having on the planet.

I found the retreat of the Columbia Glacier in Alaska; the cycles of desiccation of Lake Poopó in Bolivia; and rising sea levels in Subarnachar Upazila, Bangladesh three particularly eye-opening and relevant examples. If you’re not convinced by the scale of the problem we’re facing, these might help change your mind. Have a look and let me know what you think.

Arctic Sea Ice

Arctic sea ice isn’t often out the news these days. Whether it’s used by climate scientists as a warning of things to come or by ‘sceptics’ as proof that things aren’t as bad as claimed, it seems the world is very interested on what’s going on up there.

It can be hard to know what to make of all this. One way to visual what’s going on is with Andy Lee Robinson’s 'Arctic Death Spiral'. (Note: many of the graphics this week are from tweets, to ensure their creators are properly credited. This doesn't mean they are poor science though; you can see the source of the data in each of the images. Have a look at those links if you want to find out more!)

#Arctic Death Spiral - October 2016 average vol: 5,539 km³ - 2nd record lowest (last year 7,052 km³, 2012: 5,036 km³) pic.twitter.com/zXmqkYy8dV

— Andy Lee Robinson (@ahaveland) November 14, 2016

Figure 1: The average area covered by sea ice in the Arctic each month since 1979 until October this year.

Each month has its own spiral because the amount of ice in the arctic changes dramatically over the year. As you can see from this graphic, the ice generally peaks around April and is lowest in September, and has dramatically decreased over the last few decades. After September, temperatures drop again and ice begins to form again. Worryingly however, this November has been anomalously warm; up to 20˚C warmer than average for this time of year. This has resulted in a record breaking lack of ice.

Okay, maybe time to let the #Arctic know what season it is -> another drop in #seaice extent from the last 24-hours (3rd day in a row, JAXA) pic.twitter.com/2Fl1pQUsD4

— Zack Labe (@ZLabe) November 20, 2016 

Figure 2: Arctic sea ice extent this month is lower than ever observed at this time of year.

In fact, as of Wednesday, over half the days this year have broken the record for the lowest extent of sea ice for that time of year.

2016 has now broken daily record min Arctic #seaice extent on exactly 50% of days so far this year. Crazy year in the Arctic! pic.twitter.com/crW9rdc3pV

— Zack Labe (@ZLabe) November 23, 2016

Figure 3: This year's Arctic sea ice cover anomaly relative to the previous record minimum for that date.

So what about all those articles asserting that the situation isn’t all that bad? Many are based around overly pessimistic predictions made during the record minimum of 2012 (see figure 4). The absolute minimum has not been this low since, with this year’s September minimum the same as that seen in 2009 (making it the joint second lowest coverage on record). However, although the terrifying event of 2012 is yet to be repeated, as figure 1 shows there is still a very significant decreasing trend. This trend is still outside the worst case scenarios predicted by early models (shown in figure 4). All in all, not all that reassuring, despite what the Daily Mail wants you to think.

Figure 4: Image from Skeptical Science during the record 2012 minimum compared to model projections.

The recent Arctic Resilience Report doesn’t provide much comfort either. It highlights the vulnerability of the Arctic to climate change, and lists 19 tipping points we are approaching there. This video from The Guardian summarises some of the most important (and terrifying) points from the report.

In summary, despite what can be taken away from cherry-picking data or very short term variability, we are seeing a significant and rapid loss of Arctic sea ice. This has the potential to have dramatic knock on consequences on the rest of the world. And if you’re still not convinced of the seriousness of this issue, just remember: no Arctic sea ice= no polar bears. Time to act.

Climate pessimism

This week there has been a lot of pessimism regarding climate change in the news, largely due to the result of a certain election. For the sake of my sanity we are not going to dwell on said result, but instead look at a different gloomy story in the news this week. The Independent summed up the media stories well with this headline: ‘Climate change may be escalating so fast it could be 'game over', scientists warn. New research suggests that the Earth’s climate could be more sensitive to greenhouse gases than previously thought, raising the spectre of an ‘apocalyptic side of bad’ temperate rise of more than 7C within a lifetime’.

So are scientists actually warning this? The news articles are based on a paper published in Science Advances this week. The scientists in question were aiming to test current projections of how the Earth’s climate system will respond to increasing CO₂ using data about past climates.

They reconstructed a global surface air temperature record for the last 784,000 years, using sea surface temperature proxies from across the world. They then correlated this to records of atmospheric CO₂ (from air bubbles trapped in ice sheets), and used this to assess the sensitivity of the Earth’s climate system to changing CO₂ levels.

Box 1- SST proxies On much of the ocean floor sediment builds up gradually and constantly over time. This sediment often contains indicators of conditions at the time it was deposited- a climate proxy. A commonly used example (including in this paper) is the calcite shells of microorganisms called foraminifera. Depending on the species, the chemical and physical make up of the shell can give us a lot of information about the climate and water the shell formed in. The ratio of different oxygen isotopes (commonly written as δ18O) can give information about temperature and ice volumes at the time, as can other relationships such as the ratio of calcium to magnesium or the direction the shell coils in. By taking cores of sediment containing these proxies, scientists can reconstruct an accurate picture of how climate changed over the period the sediment was being deposited. Henderson (2002) provides a more detailed discussion of a number of proxies if you’re interested in learning more.

They found that there results were generally in good agreement with the projections they looked at. These were from CMIP5 (the coupled model inter-comparison project 5) which provided the projections used in the 5^th IPCC report  (see previous blog post) . It’s worth noting that all projections come with significant uncertainty- we don’t really know how things like cloud formation will feedback into climate responses. This is why when you see projections on graphs there is not a thin line, but a thicker band. The results from this study are well within the CMIP5 uncertainty range, but the maximum emissions scenario shows temperature increases by 2100 around 16% higher than the mean of the projection.

Figure 1: CMIP5 projections based on different emissions scenarios (here called RCPs). RCP8.5 is the projection referred to in this paper.

This is where the headlines come from. The study found that as the climate warms it becomes more sensitive to CO₂ i.e. that there is more warming per unit of CO₂. This might put the Earth at risk of ‘runaway’ climate change- where positive feedbacks amplify warming and the system spirals out of control. 7˚C would indeed be catastrophic, but these projections are based on high emissions scenarios where we do nothing to reduce how much CO₂ we produce. If we stick to our 2˚C ambitions we stand a good chance of avoiding runaway change.

One criticism of this paper is that over the period studied CO₂ levels have never been as high as they are today, never mind how high they would be in the worst case scenarios referred to in the headlines. They therefore cannot test climate responses to the type of climate forcing expected later this century. However, this paper finds good agreement with previous studies looking at longer time periods in which CO₂ was higher, for example Köhler et al (2015), who looked the last 5 million years.

So the two main takeaways from this post (apart from never trust a headline) are:

1.       There is more and more evidence that in the past climate responded to increasing CO₂ in a similar way to the way CMIP5 models suggest it will in the future. This means we have more confidence in the projections in the IPCC report for example. So if we stick to the 2˚C pathway we're in for a decent shot of avoiding the apocalypse.

2.       The warmer the world gets, the greater the effect additional CO₂ emissions will have on climate, and the more uncertain we are about its impacts. The more we emit, the higher the risk that the climate system spirals out of control. Even more of a reason to cut emissions fast!

Let’s hope the world’s leaders are ready to take bold actions to save the planet. Oh wait...

COP21

In December 2015, leaders from across the globe met in Paris at the UNFCCC’s (United Nations Framework Convention on Climate Change) COP21 conference in Paris. 197 countries signed a historic agreement committing, for the first time, to limit total global temperature increases to ‘well below’ 2˚C above pre-industrial levels. It was also recognised that a target of 1.5˚C would be more desirable. The Paris Agreement  is the the topic of this blog post because today it entered into force. This means that countries which have ratified the treaty (a total of 97 counties responsible for 66% of global emissions) are now legally bound to it.

This is certainly a big step forward, and when the agreement was signed in December, and again today on its implementation, there were a swath of celebratory headlines. For example, both CNN and The Guardian published articles labelling it ‘the end of fossil fuels’. Others however were critical.

So what’s the true story? Admittedly, amongst the hysteria there were a number of articles that were balanced and accurate. However, I think the best analysis is in the UNEP (United Nations Environment Program) Emissions Gap Report, the launch of which I was lucky enough to attend yesterday. The report looks at whether countries are sticking to previous climate commitments, such as Cancun 2020 pledges, and what impact the Paris Agreement may have. It’s a very interesting read, and I’d really recommend having a look using the link above. 

In short, it identifies a significant gap (hence the name) between current pledges and actions and those needed by 2030 to keep us on track for the 2˚C goal. According to their analyses, annual emissions will need to be reduced to 42 Gt CO₂ (1 gigatonne (Gt) = a billion tonnes) by 2030 to have a 66% chance of meeting our 2˚C target. Based on the pledges made at Paris (see Box 1) we are projected to be 12-14 Gt above this. This would result in a temperature increase of 3.4-3.7˚C.

Box 1: INDCs After the failure of the 2009 Copenhagen summit due to countries being able to agree how to split the responsibility for reducing emissions, a new approach was sought. Each country came to Paris having decided their own emissions reductions pledges, or ‘Intended Nationally Determined Contributions’ (INDCs). This did resulting in successfully reaching the groundbreaking agreement to limit warming to 2˚C, but the total of the INDCs is not sufficient to get there. Furthermore, some INDCs were conditional, for example on financial aid.

Image 1: Projected possible emissions pathways, based on business as usual, current policy, and Paris pledges scenarios. Image taken from the UNEP Emissions Gap Report.

Overall then, the Paris Agreement shows governments across the globe are taking the threat of climate change seriously and are willing to take serious steps to combat it. It also shows the potential for global diplomacy, and is a cause for optimism in this sense. However, it does not represent a ‘solution’ to climate change. We are still a long way off a point where global leaders reach an agreement that will actually achieve the aim they signed up to Paris. 

Wine- the real crisis

This weekend, I woke up to a horrifying message from a friend. This screenshot from mic.com.

In all seriousness, whether or not wine will become more expensive or harder to come by as the effects of climate change begin to be felt is a minor issue (understatement of the century) compared to other predicted effects, particularly those affecting people in the Global South. However, given how widely reported this story has been I thought it would be interesting to check out the science behind it.

The headlines were triggered by the International Organisation of Wine and Vine’s (OIV) latest report. It reports a fall in total production of 5% compared to 2015, making this year’s production among the three worst this century. 

Image 2: Trends in global wine productions using OIV data.

It has been reported in many articles (including in The Guardian, CNN and The Independent) that this is attributable to climate change. In the OIV’s press release they briefly mention that South America was ‘strongly affected by climatic events’. The OIV’s Director General reportedly added “output was greatly affected by exceptional weather conditions. If there is one product that is vulnerable to weather events, it’s wine,” and "with global warming, we're witnessing an increase in exceptional events that are more frequent, longer lasting and of greater scale."

Let’s examine these claims one by one.

Firstly: could ‘climatic events’ really explain the fall in production in South America? The climatic event in question is El Niño, a reversal in usual weather patterns in the South Pacific. It causes dramatic changes in rainfall patterns and temperatures across the Southern hemisphere. This year’s El Niño is one of the most powerful ever recorded and had massive impacts, including droughts in Brazil and floods and landslides further south. It’s pretty much inevitable that destructive climate events of this scale result in overall reductions is agricultural productivity, and grapes are no exception.

It’s also true that climate change is likely to exacerbate these effects. There has been a lot of speculation and debate for a long time about how climate change may affect El Niño events, but a recent study concludes that these events will become stronger and more frequent with climate change.

But what about elsewhere? Much of the decrease in production is indeed attributable to South American countries. For example, production in Brazil decreased by 50%. However many other countries also saw a fall in wine production. The biggest absolute decrease in wine production occurred in France, which accounted for more than a third of the total global decrease.  El Niño mainly affects the South Pacific and neighbouring regions, and although it is true that more local climate events can have knock on impacts around the globe, it is unlikely that El Niño was the sole cause of wine production decreases in Europe.

So could anthropogenic climate change also be affecting wine production? A 2014 review paper published in the journal ‘Wine Economics and Policy’ suggests climate change will affect wine production in a number of ways, including reducing both productivity and the land available for vineyards, requiring changes in grape varieties grown, causing fundamental changes in wine chemistry, and increasing pests and diseases attacking vines. It also corroborates the above statement about the susceptibility of grapes to changes in climate (although given that the paper features the line ‘wine is not essential to human survival’ some may be inclined to reject its findings completely).

Another paper published in Nature Climate Change earlier this year compared past climate records to vineyard records in France and Switzerland. It found that although recent climate change has in fact resulting in some outstanding vintages, the current decoupling of summer heat waves and droughts is likely to negatively impact future wine production. 

It seems that the assertions in these media stories are true. However, as is often the case, the headlines don’t accurately represent the actual stories or the OIV report they’re based on. The OIV’s tiny mention of ‘climatic events’ refer to the most recent El Niño,and the Director General’s follow up comments (rarely even mentioned in media stories) to its interaction with climate change.  Headlines such as ‘Attention wine lovers: You might want to start paying attention to climate change’, while factually correct, don’t accurately reflect the article or the report on which it is based.

Looking at the graph above, it s also clear that this year’s overall production, although genuinely lower than recent averages, is not as low as headlines like ‘Global Wine Production Is Collapsing Thanks To Climate Change’ suggest.

As always then, this story is a reminder to always take media hysteria with a pinch of salt. And if in doubt about the science- send it this way!

The world's biggest hoax? Part 2

This post follows on from last week’s post and aims to answer the question: does evidence support the idea that human activity has played a significant role in this change?

Most people have probably heard the story of CO₂ and the greenhouse effect, but here’s a diagram to recap.



Figure 4: How greenhouse gases like CO₂ cause the Earth to warm.

You may well have seen in the news recently that CO₂ reached a permanent concentration of 400ppm in theatmosphere, which probably means nothing to you until I tell you that’s the highest it’s been for over 800,000 years. The IPCC states that CO₂ is the largest single contributor to increases in temperature between 1750 and 2011.

As is commonly pointed out by sceptics though, CO₂ has many natural sources- so who’s to say us burning fossils fuels is to blame? Well, apart from the fact that we know we’ve burnt enough fossil fuels to contribute that much CO₂ to the atmosphere, CO₂ from fossil fuels has a chemical signal that means it can be identified.

Box 2: The Suess Effect (for those who like chemistry) Carbon has three naturally occurring isotopes: C12, C13 and C14. During photosynthesis, the different carbon isotopes are not absorbed with equal preference, leading to plants and algae being depleted in C13.  As fossils fuels were once live organisms, they too carry this isotopic signal. C14 is also depleted in fossil fuels as it is radioactive. As its half life is close to 5000 years, over the millions of years fossil fuels take to form most has decayed. By monitoring changes in the ratios of different carbon isotopes in the atmosphere we can calculate the contribution of CO₂ from fossil fuels. This was first noted by Hans Suess, and so is named the Suess effect.

It’s not just fossil fuel combustion either- greenhouse gas emissions (22% of the total according to the IPCC) also come from other human activities, such as methane from farming and CO₂ from deforestation.

The above evidence has contributed to the IPCC being able to state that ‘It is extremely likely that more than half of the observed increase in global average surface temperature from 1951 to 2010 was caused by the anthropogenic increase in GHG concentrations and other anthropogenic forcings together. The best estimate of the human induced contribution to warming is similar to the observed warming over this period.’

In other words, the very best interpretation of all the very best evidence by the very best collaboration of climate scientists suggests that we are causing the most extreme climate change seen on Earth for thousands, if not millions of years. I can’t argue with that.

The world's biggest hoax? Part 1

In future I’m going to have a look at specific, recent stories about climate change in the media, but I thought I’d write the first proper post here on arguably the biggest question surrounding anthropogenic (human-caused) climate change: is it really happening? This is a big topic so I’m going to split it into two posts.

The arguments against anthropogenic climate change come in several forms. Some deny that climate change is happening:

Snowing in Texas and Louisiana, record setting freezing temperatures throughout the country and beyond. Global warming is an expensive hoax!

— Donald J. Trump (@realDonaldTrump) January 29, 2014

Others, such as more than half the US Senate, recognise that the climate is changing but refute humanity’s role. Many point to past changes in both climate and CO₂ as evidence that current changes are natural or within ‘normal variation’, and deny that there is a scientific consensus regarding our role.

Meanwhile many media outlets regularly publish articles predicting the extreme and imminent effects of climate change, such as destroying infrastructure, worsening extreme weather events and even endangering US military operations. I hope to have a look at some of these in a later blog.

Much has been written for and against these arguments, and I can’t cover the nuances of every point in just one post. I would really recommend the Skeptical Science blog for a more detailed discussion of specific questions (thanks to Anson for the recommendation).

For now though, I will try to answer whether climate change is all a hoax by simplifying it to two key questions:

1) Does evidence support the idea that climate is changing outside the bounds of ‘normal variation’? (This post)
2) Does evidence support the idea that human activity has played a significant role in this change? (Next post)

Firstly, I’d like to share this awesome graphic from NASA. 

Figure 1: Surface temperature changes from 1880 to 2015, using a rolling five year average. Blue colours represent temperatures cooler than the 1951-80 baseline, while red colours represent temperatures above that baseline.

It seems pretty clear that temperatures have risen over the last century-and-a-bit.

Bloomberg plotted NOAA data to show a similar trend. They also highlighted the fact that 15 out of the 16 hottest years on record have been this century, and that 2015 was not only the hottest year on record, but also beat the previous record by a record margin (N.B. NASA’s data suggests the increase from 1997-8 was larger, but corroborates the fact that 2015 was the hottest year on record).

I’d say these data sources are fairly reliable. However, arguably the most reliable sources of data relating to climate change are the IPCC reports. 

Box 1: The IPCC The Intergovernmental Panel on Climate Change is Nobel Prize-winning body, established by the UN to improve understanding of the scientific basis of climate change. It doesn’t carry out its own research, but instead reviews published papers (both peer- reviewed and non peer-reviewed). Based on this evidence, it then reaches conclusions, and, most importantly and interestingly I think, attaches a degree of certainty to these. Although the IPCC has received much criticism in the past, for example over claims about the disappearance of Himalayan glaciers it is generally considered to give a fair reflection of the scientific consensus on climate change. The most recent report, its 5th, was published in 2013.

So what does the IPCC have to say about whether the climate is warming? In the most recent report it states that ‘the globally averaged combined land and ocean surface temperature data... show a warming of 0.85 [0.65 to 1.06]°C²⁰ over the period 1880 to 2012, for which multiple independently produced datasets exist’ (the figures in square brackets are the error margins). 

To me, this all seems fairly conclusive, but let’s look at one of the most popular arguments of climate change sceptics: ‘the great pause’. As the picture below demonstrates, it is a popular claim that temperatures have stopped increasing since the late 1990s.

Figure 2: The Sunday Mail’s headline and graph from October 2012.

As we saw above, warming hasn’t stopped in the last decades. The climate system is complex, and human impacts are modulated by and interact with natural cycles, such as El Niño events (which contributed to the highs in 1997/8 and 2015). We therefore don’t see a totally regular, noise-free pattern, but the short term variation does not negate the long term trend. In fact, a recent Nature paper found that hiatuses like this one are statistically inevitable when such small samples are considered.

However, even if we accept warming is occurring, this is only in the context of 130 years. We know the climate has fluctuated much more wildly in the past, with both ice ages and the sweltering conditions that accompanied the dinosaurs firmly in the public imagination. So why are modern changes any different? The IPCC states with high confidence that ‘1983 to 2012 was very likely the warmest 30-year period of the last 800 years in the Northern Hemisphere’ but this still barely registers on geological time scales. However, if we do look at a longer time scale, such as the Holocene (the last 11,000 years), it is easier to see the significance of recent changes. It is not the magnitude but the rate of warming that is alarming.

Figure 3: Adapted from Marcott et al. 2013 by www.realclimate.org. 

So far, so good (or bad for the inhabitants of planet Earth). But what about our role? Check out my next post to find out!

Fact or fiction- and does matter?

How do you know what you think you know is true? From the current US president Barack Obama stating that ‘no challenge poses a greater threat to our children, our planet, and future generations than climate change’, to current US presidential candidate Donald Trump tweeting that it’s a Chinese hoax. Or from a national newspaper in the UK being criticised by world leading scientists for reporting that ‘appears designed systematically to undermine the credibility of climate science’ to leaked emails from a top British research institute some claim showed they falsified climate science. It can be hard to know what to believe when it comes to climate change.

It’s a topic that’s receiving an increasing amount of attention from scientists, politicians and the general public- and therefore the media. However, mainstream media statements are often made without being fully backed up with evidence, and even when evidence is presented it is frequently misreported or misinterpreted. This has led to a number of ideas about climate change becoming widely accepted despite a lack of support from science. When these issues are contentious, it isn’t helped by the efforts of people who disagree with the scientific consensus, and wish to bring it into disrepute.

With issues like climate change we can't afford to be naive. The best evidence suggests that we need to take dramatic action in the next decade, and that people who are more knowledgeable about the causes of climate change are more concerned and likely to take action. Educating ourselves about climate change is therefore the first step towards finding a solution to this epic challenge. However, even the most sceptical among us don’t have time to fact check everything presented to us by the media and politicians, or even friends, family and colleagues. In this blog I’ll take a look at some current media stories about climate change and what published, peer reviewed scientific papers reveal about their accuracy. So all you have to do is read! I’d love to hear your feedback, so please get in touch with questions, comments or suggestions as to what I should tackle. Thanks for reading, and I hope you enjoy what’s coming up!

Image 1: Probably a myth...