Climate change: what could possibly go wrong?

Credit: pixabay

Explain the basics of the blanket effect 

It's like this. The greenhouse effect is like Manchester United, an unrivalled explanation of how CO2 emissions warm the planet. Then along comes a noisy neighbour, which explains the process even better, and buys up all the best players/feedbacks.

The greenhouse effect is a flawed description of how the Earth is warming, because a sealed greenhouse doesn't let much warm air out or cool air in. That's how it stay warm. The blanket effect is a way of describing the effect greenhouse gases are having on the Earth and its atmosphere. The Earth is warmed by heat from the Sun. Some of this heat is radiated back into space; however, the blankets of greenhouse gases prevent some of this heat radiation, and cause it to be reabsorbed, warming the Earth.

Describe one positive and one negative feedback mechanism in the climate system 

A positive feedback is like this: climate change sceptic Donald Trump is elected president of the US. He promotes policies that increase both global warming and the number of climate sceptics. This makes people less likely to make behavioural changes that limit global warming. Coal and fracked gas production increase, thus warming the planet further.

A negative feedback is like this: climate change sceptic Donald Trump is elected president of the US. He promotes policies that increase global warming. This results in sea level rises, severe weather events, and a melt in the permafrost. The melting permafrost opens up new opportunities for hydrocarbon exploitation in Russia. However, a 3,000-year-old virus is also released from the permafrost, decimating the global human population and greatly reducing anthropogenic greenhouse gas emissions, resulting in a cooling planet and the permafrost resealing over.

Or perhaps it's more like this: A positive feedback mechanism in the climate system is ice albedo. The release of CO2 causes the planet to warm. This reduces ice cover in the polar regions. Reduced ice cover means a lower albedo, that is, less solar radiation is reflected back into the atmosphere from the earth's surface. This increases warming, which decreases ice cover.

A negative feedback mechanism in the climate system is silicate weathering. When it is warmer, it rains more. This increased rainfall weathers rocks, causing soil and stones to fall into the oceans. In the oceans, this weathered material connects with CO2 that has been absorbed by and dissolved into the oceans. This binds the CO2, preventing it from being released. Taking CO2 out of the atmosphere has a cooling effect, reducing rainfall, this reducing silicate weathering. A negative feedback loop enables the Earth to keep its temperature balanced.
Source: https://www.scisnack.com/2015/08/04/why-negative-feedback-is-good-for-the-climate/

Put contemporary climate change into the context of past, natural variability

'Aint nothing new under the sun,' King Solomon moaned in Ecclesiastes, and when it comes to a changing climate, the grumpy monarch was right. Climate change is not a modern phenomenon, and the Earth has previously experienced cycles of cooling and warming.

So what's all the fuss about then? Well, previous cycles of climate change have taken place over much greater periods of time (hundreds of thousands of years); the speed of change in the Earth's temperature over the past 200 years is unprecedented. Slower change has allowed the Earth to adapt, and feedbacks to kick into place. The current level of CO2 in the atmosphere is problematic because it is putting unusual stress on the Earth's natural ability to absorb CO2 and cool itself.

Review the evidence for human-induced climate change 

Since about 1750, the energy reaching the Earth from the sun has remained largely constant. However, the global average temperatures of the land and the sea have risen dramatically. Therefore, there must be an alternative explanation. As part of industrialisation, much of the world has been burning fossil fuels, releasing carbon that would otherwise have been released over a much greater timescale, if at all. This CO2, and other greenhouse gases, are adding layers to the blanket of gases around the Earth, letting less heat escape.
Sources: https://www.skepticalscience.com/empirical-evidence-for-global-warming.htm and https://climate.nasa.gov/evidence/ (two sources among many. Seriously, climate deniers, time to come up with a new excuse)

Explore the impacts of climate change on the cryosphere 

It's not called the cryosphere because of all those heart-rending pictures of polar bears floating around on pieces of ice so small you could stir them into your G&T; the cryosphere is the really, really, cold bits of the Earth, like Alaska, Antarctica and Theresa May's heart.

It is in the cryosphere that some of the effects of global warming are most apparent. Global warming is causing all of the following, to a greater or lesser degree: melting glaciers, shrinking sea ice and sea ice forming later in the year and for shorter periods of time, reduced albedo. The positive feedback of albedo means smaller ice sheets could accelerate global warming, resulting in melting of land ice, including the permafrost. Melting of the permafrost could provide another positive feedback because of the levels of methane stored in the frozen soils.
Source: https://serc.carleton.edu/eslabs/cryosphere/5b.html

Evaluate the vulnerability of the oceans to ‘the other carbon dioxide problem’ 

The oceans have absorbed much of the CO2 that has been released, both naturally and anthropogenically. This has been largely positive, because it has curtailed warming on the land, protecting us from some global warming.

However, the higher levels of CO2 have resulted in ocean acidification - climate change's noisy, troublesome and extremely irritating little brother, who is, basically, getting high on hydrogen ions and spoiling the party for everyone.

Carbon dioxide links with water and carbonate in the water to produce bicarbonate, reducing the availability of calcium carbonate in the water. This is having startling effects on marine life: marine creatures with shells or skeletons are finding it harder to get the calcium carbonate they need to form properly (so Nemo's probably OK but Sebastian, the amusing lobster from Little Mermaid, is in trouble). This is likely to have have ramifications higher up the food chain, including for human fish consumption.
Sources: https://www.pmel.noaa.gov/co2/story/What+is+Ocean+Acidification%3F; https://www.eartheclipse.com/environment/causes-effects-solutions-of-ocean-acidification.html; http://www.epoca-project.eu/index.php/what-is-ocean-acidification.html

Discuss how scientists model future climate scenarios 

Scientists use a variety of methods - ice cores, tree rings, pollen, sediments and corals - to investigate what the climate was doing in the recent and distant past. To build climate models, climatologists feed data from known climate inputs (such as water vapour, sun radiation, CO2 levels) and run them using historical data. This enables them to see whether the modelling is a reliable prediction of future climate.

The unknown in this area is human activity. The number of humans there are and how much fossil fuel they burn will greatly determine the climate.

Reflect on the role humans are playing in changing the Earth system 

Higgledy piggledy
Gorging on fossil fuels
Making us hotter than
We rightly should be

Much of the warmth is caused
Anthropogenically
Which basically means
That the problem is me

Update: Nya Murray on the climate change course has compiled a much more comprehensive list of useful climate change links so thanks very much to her. 

Some of the links I've found useful on this course: 

• http://www.enviropedia.org.uk/ 
• http://anthropocene.info/tipping-elements.php 
• https://www.youtube.com/watch?v=Lgh3Obf4LeA 
• https://www.sciencealert.com/this-map-shows-the-parts-of-the-world-most-vulnerable-to-climate-change 
• http://www.climatehotmap.org/ 
• https://www.carbonbrief.org 
• http://www.un.org/sustainabledevelopment/takeaction/ 
• https://www.metoffice.gov.uk/climate-guide 
• https://theconversation.com/uk/topics/climate-change-27
• https://www.theguardian.com/environment/climate-change
• https://www.nasa.gov/topics/earth/index.html

The hardest thing you'll ever learn is ... climate modelling

Credit: pixabay

1.
a) where is the final ice-edge? pass
b) what are the mean temperature and mean albedo? 15C and 0.31
c) what are the approximate temperatures at the pole and the equator? -15C and 0C
d) does this look like the real Earth? No, these temperatures are lower than the real Earth

2.
a) what is the mean temperature and albedo in the absence of heat transport? 9C and 0.34
b) at what K value does the model become completely ice-free? pass
c) what are the implications of this sensitivity to K with regard to variations in poleward heat transports (e.g. variations in the Gulf stream)? Is this realistic? pass

3.
a) By reducing the “Fraction of Solar Constant” in Run 1 determine the value at which the Earth becomes completed ice-covered. 0.88
b) Set the initial ice-edge to 0o (i.e. “Snowball Earth'”) and increase the solar constant from the value found in (a). At which value does the ice-sheet completely melt? 1.2
c) Set the initial ice-edge to 90o (i.e. ice-free Earth) and reduce the solar constant from the value found in (b). At which value does the ice begin to reappear? 0.88
d) Sketch phase diagrams of mean albedo versus fractional solar constant, and mean temperature versus fractional solar constant. Initialise Run 1 and Run 2 with ice-edges at 0o and 90o, and increase the solar constant values from 0.8 to 1.2 in steps of 0.05. Fill in the mean values of temperature and albedo in the workspace table at the bottom of the “Graphs” sheet. This will produce phase space diagrams below the table. Wow, a big jump (+60C) in temperature between 1.15 solar constant and 1.2
e) Given that the Sun was fainter in the past, what do these diagrams “predict” the current Earth state should be? What missing processes might resolve this “faint young Sun paradox”? The Earth should be cooler than it is. The missing process is the warming effect of CO2.

4.
a) What is the impact of doubling CO2 on global temperature and albedo? Mean temperature increases by 3.44604C and albedo decreases by 0.009162
b) Why does this differ from the T2x input parameter? Because this input parameter assumes 0 albedo
c) The global mean temperature is given by : = [ {1 - <>} – A] / B where =1370 fS / 4 is the mean incident solar radiation, <> is the mean albedo, and B=2.17 W m-2 oC-1. Derive a relation between the increment to the mean temperature due to albedo changes, Tsnow , and the albedo change itself, . Does this fit with the answers given in (a) and (b) above? pass
d) Now try 4xCO2 in Run 1. How large are the mean temperature and mean albedo changes in going from 2xCO2 to 4xCO2? Why are they lower than in (a)? Mean temperature increases by 2.00086 and albedo decreases by 0.000005.

Ocean acidification ... now that's gonna sting

Credit: pixabay

Into week three of my Future Learn/University of Exeter (which looks like such a wonderful place to study) course on Climate Change: The Science, and this week we've been looking at the oceans and wondering what those beautiful clownfish ever did to deserve what's being thrown at them, climatically speaking.

As I write this, I'm eating Raffaello chocolates from Ferrero Rocher, and wondering where all the plastic that consumes* them is going to end up.

"Ambassador, with these Ferrero Rocher you are really spoiling the ocean" 

OK, three questions to answer:

1) What is the effect of acidification on marine organisms? 

Now, marine organisms is quite a broad term. Big fish, little fish, probably a cardboard box or two as well.

So first, a quick explanation of ocean acidification (OA) as I understand it. Humans have been releasing a lot more carbon dioxide into the atmosphere over the past 200 years than the Earth has been accustomed to. About 30% of this has been absorbed by the oceans. This is good (at least in the short-term), as it has kept a rein on global warming on land.

However, the high levels of CO2 in the seas are causing a chemical shock for many of the creatures that live there. Mixing water and carbon dioxide allows carbonic acid to form. Acids release hydrogen ions. Hydrogen ions are flirtatious little sods and want to get hooked up with anything going. One of the things going is carbonate.

But carbonate is much in demand as marine organisms use it to make shells and skeletons. As carbonate heads off into the sunset with hydrogen ions, (in the form of biocarbonate), certain marine organisms are left feeling a little, well, naked. Lazy. Fed up. Basically they have to spend a lot more energy on making their shells, leaving less for eating, reproduction and growing properly. They mope, essentially.

One of the major problems is that a lot of these carbonate-dependent organisms are at the bottom of the food chain. If they become fewer in number, or smaller, that causes problems for marine organisms higher up the food chain. Fish people might care about a bit more, perhaps.

Other reported impacts of OA include reducing the smells, sights and sounds of the oceans, which can affect marine organisms' ability to find habitats and food, and escape predators.

I should point out that some marine organisms are likely to thrive in a CO2-richer environment. But it'll probably be the ugly ones, or the really rubbish ones that are essentially plants anyway, not the pretty tropical fish.

2) Are there any economic effects from your chosen impact? Which areas might be hit the hardest? 

Early days. In fact, the study of OA as a whole is rather nascent compared with other aspects of climate change. Heck, the Guardian doesn't even have a keyword for it yet! So direct economic impacts are hard to predict. However, fish is a vital source of protein for millions of people - constituting 70% of protein intake for some island and coastal countries, according to the Food and Agriculture Organisation. Declining fishing stocks would have a severe impact on food security and on people working in the fishing industry. And some of those people - those who can afford it - will turn to meat as a protein source, and increasing meat demand could produce a positive feedback as many sources of meat (particularly cows) contribute to global warming (by farting and deforestation).

3) What’s the most effective solution to preventing your chosen impact? 

There is emerging evidence that growing more sea grass could help, by absorbing marine CO2. A bit like planting trees on land. Limiting consumption of affected species of fish by those who can, while not directly changing the pH balance of the sea, could allow those species under most stress a greater chance to adapt or recover. But, in a nutshell, we need to stop releasing so much CO2 into the atmosphere. Simples...

Additional sources: Simthsonian, WWF, NOAA

*OK, so it's actually me consuming them.

Climate change: in it for the long haul

Credit: pixabay

How does the climate vary naturally over millennial time scales?
Can contemporary climate change be explained by natural variations?
What is the evidence for climate change? 

1) Put simply, the climate gets warmer and cooler again, in its natural and delicate balancing act. The most obvious example of a climate feedback is the ice albedo feedback: larger ice cover reflects more radiation back to space, keeping it cooler. As ice cover decreases, more radiation is absorbed by the darker coloured water, and the temperature rises. Part of the reason for the Earth's changing climate over millennia are slight changes in the Earth's orbit around the sun.

2) The evidence for contemporary climate change exceeds the temperature ranges previously seen in natural variations, suggesting there must be another factor at play to explain the extremes we are seeing now. Data also suggest that the climate is changing at a much greater speed than previously seen in natural variations. The US Forest Service explains it succinctly:

"Climate varies without human influence, and this natural variation is a backdrop for the human-caused climate change occurring now" 

3) Some climate deniers would have you believe that the evidence for climate change is largely disputed, anecdotal and insubstantial. It isn't:

• rising sea levels
• decreasing ice cover
• rising levels of CO2 and other GHGs
• rising global average temperatures on land and sea

Sources: The Royal Society; Nasa; Inside Climate News

The past is a foreign country: they do climate differently there

Credit: pixabay  

What can we learn from the past? Is it important to know about the climate on timescales that are almost incomprehensible to our human lifespans?

Timescales give ammunition to climate deniers as they can say, 'we survived before and we'll survive again' (glossing over the fact that 'we' was very different then, and didn't include humans).

The fact that we know how extreme the PETM was, and there is still no global urgency to combat a warming planet, suggests the fear factor isn't working. I think most people in the developed world are aware of climate change but also know they will be protected from the worst effects of it by time (they'll be dead), location or money.

There have been a few comments (on the discussions boards of the University of Exeter's Climate Change: The Science course) damning politicians for a lack of action. I've nothing against damning politicians, but - while you can cite eco 'gestures' for most countries in the world - no country is leading on climate change - the inertia is terrifyingly widespread. This is no doubt partly because, again, of the timescales involved - election in four years' time vs data from 56 million years ago - but also because there is not one set of actions agreed upon that would halt climate change.

Somebody mentioned they felt switching their TV off standby was worthless in the face of massive industrial and leisure projects that guzzle energy and belch carbon. I think some politicians and countries also feel like that (it's certainly a theme that has emerged at previous climate talks) - why should I risk my political career/country's economy/unemployment stats if my neighbour consumes coal like it's jelly babies?

And green issues are so broad that it's difficult to ascertain what is specifically an action to limit - I don't think we can say prevent any more - global warming, and what is a more generalised environmentally friendly way of living. And people are full of contradictions - using a reusable coffee cup and flying lots; religiously recycling all their meat trays; driving to the organic supermarket in a diesel car.

One thing that hasn't been mentioned yet much in the threads is population. Part of the horrors of plastic are not simply because of plastic per se, but because of the sheer volumes of it that 7 billion people use. Same with greenhouse gases.

Technology is a way forward, perhaps the only way. People don't invent (or mass produce) a climate-saving device, such as compostable packaging, carbon capture and storage, solar panels, a TV that turns off automatically, until the demand is there. And when it comes to selling stuff, the world listens more to consumers than politicians.

It's getting hot in here, so take off all your clothes (in an attempt to reverse the Paleocene-Eocene Thermal Maximum)

Credit: pixabay

Alarm bells are not subtle things. Think car alarms going off outside your window in the middle of the night, or the neighbours' burglar alarm going off the day after they've gone on holiday for a fortnight. Alarms are there for a reason. They are intended to make us stop what we're doing and take action.

Planet Earth is warming. Regardless of the whys, and the variety of means to combat temperature rises, if it ends up becoming uncomfortably hot then we can't say we weren't warned. It's happened before.

Step in the Paleocene-Eocene Thermal Maximum. This refers to when it got really hot earlier in the Earth's life (I would give you the exact number of million years, but I find numbers bigger than 100 tend to turn people off. We just can't conceptualise time over such a great span).

Anyway, when the PETM happened, you could have caught Santa sunbathing in the north pole. Some of the impacts are similar to things happening now: the oceans becoming more acidic and sea levels rising.

It also caused some species of organisms - that's precursors to cute animals - to become extinct and ecosystems to migrate. Climate refugees, if you like.

Yes, the planet recovered after the PETM. But this time it's happening much more quickly. According to the University of Exeter (which is running the fascinating Climate Change: The Science course that I'm taking part in):

"The PETM had warming of around 0.025˚C per 100 years. Currently, we’re on track for around 1˚C of warming per 100 years" 

As part of the course, we're asked:

• Do you think the PETM has some similarities with today’s climate change? 
• What lessons can we learn from this event to ensure the impacts don’t happen again? 

Undoubtedly there are similarities; a large dumping of CO2 occurred, and it warmed the planet significantly and, by geological standards, quickly. What's more alarming is the difference: the PETM occurred much more slowly than the current anthropogenic climate change we're experiencing. And although some of the outcomes are undoubtedly similar, the Earth is a very different place to the one that experienced the PETM. For a start, there are 7 billion humans on it. 

I'm not sure of the lessons learned yet. There seems to be a lot of carbon stored in the ground, so I'm thinking drilling is probably going to be a bad idea. The PETM showed that the Earth heats up a lot more quickly than it can cool itself down again. Has anyone measured the comparative speeds of positive warming and cooling feedbacks? And also, what's the role of trees? Is the albedo effect solely to do with the reflective properties of ice and snow, or are they also cooling because they don't support vegetation? And are trees as important a carbon sink as carbon stored in rocks and volcanoes?

Sources: Future Learn / The University of Exeter

I'll be 490 by the time …

… all the nappies I've used (on my children) have decomposed. That's shocking, and sad.

Image from https://earthrespect.wordpress.com/

Climate feedbacks ... remind me what they are again?

Credit: pixabay

Still, as a non-scientist, trying to get my head around climate feedbacks and found a couple of useful things: a graphic, a definition and a list of climate feedbacks (most of which is a bit detailed for me but still interesting).

Credit: www.powerplantccs.com/Met Office

Here's the definition, also courtesy of the above website:

"An interaction between various processes of climate system is called climate feedback, where in the result of one process triggers changes in the another process that in turn will influence the initial one. There are many climate feedback mechanisms that can either amplify or diminish the effects of climate change contributing factors. A positive feedback is one that can amplify the effects of climate change while negative feedback is one that diminishes the same."

And a list of the climate feedbacks, positive (but not good!) and negative.

The above link contains an interesting paragraph on clouds, which I hadn't really thought about other than often finding them pretty or portentous:

"Clouds are the elephant in the living room. They're obviously extremely important, but they are very poorly understood. High, wispy cirrus clouds have a warming effect, because they are made of ice crystals, which makes them much more nearly opaque to outgoing longwave infrared than to incoming visible and near-IR solar radiation. Lower clouds, which are made of liquid water droplets, have a strong cooling effect in daytime, but a warming effect at night. How clouds are affected by warming or cooling climate is very complex."

Nitrous oxide, the funniest of the greenhouse gases ...

Credit: pixabay

I'm taking part in Future Learn and the University of Exeter's course on Climate change: the science. This is my first bit of research, on N2O. Bear with me, it's week one and it's a long time since I did GSCE chemistry.

My research questions are:

• Which human activities lead to the emission of your chosen greenhouse gas? 
• What is the impact of your chosen greenhouse gas on the blanket effect? 
• How will your chosen greenhouse gas impact important climate feedbacks? 

I chose N2O, cos CO2 is a bit passé.

The main human activities that contribute to N2O emissions are farming and the massive increase in the addition of nitrogen fertilisers to the soil over the past 100 years in order to produce more food to feed a growing global population. Microbes link the nitrogen in the soil with oxygen in the air to form N2O.

In a similar way, changes in land use also release N2O, particularly converting forest land to pasture for grazing animals.

Other human activities that emit N2O include: burning fossil fuels and wood; sewage plants; nitric acid manufacturing.

N2O has an impact on the blanket effect as, although there is much less of it in the atmosphere than water vapour or CO2, it traps heat more effectively than other GHGs do. Also, it lasts in the atmosphere much longer than other GHGs, resulting in a much higher global warming potential.

There are four key ways in which N2O affects climate feedbacks:

1. N2O depletes the ozone layer as it passes through the atmosphere, reducing the protection that the ozone layer gives against the warming effect of ultraviolet radiation from the sun. 
2. Using nitrogen fertiliser results in N2O emissions, which increase global warming. A warmer planet means more CO2 in the atmosphere, and plants may require more nitrogen fertiliser if there is more CO2 in the air. 
3. Global warming is thawing the permafrost in Arctic regions. This thawing releases more N2O as microbes in the soil link the nitrogen in the soil with the newly accessible oxygen in the atmosphere. 
4. Loss of nitrogen from the soil through soil degradation and runoff makes it harder for plants to grow, and plants are important for containing global warming as they remover carbon dioxide from the atmosphere. 

Sources: BBC; Nasa; the Conversation; Global Change Biology journal; Earth Island Journal.