Arguments
Effects of Global Warming
Posted on 3 June 2019 by Riduna
Why are young – and not so young – people becoming more vociferous in their protests about global warming? Why has climate change become a political and partisan issue at democratic elections? Why do ‘greenies’ try to stop the development of new coal mines and call for speedier reduction of our greenhouse gas emissions? The answer is that the effects of greenhouse gas emissions, particularly Carbon Dioxide (CO2), are becoming increasingly evident and dangerous – although relatively mild at present, compared to what they could soon become.
Much is being said about the cost of reducing greenhouse gas emissions in terms of lost jobs, lost income and harm to national and global economies but we hear relatively little about the catastrophic consequences of not reducing emissions. Prioritising short term profit and ideology ahead of emissions reduction will inevitably result in an uncontrollable, unpredictable and destructive climate resulting in socio-economic collapse.
Fig. 1. Fluctuations in the level of CO2 in the atmosphere, relatively regular until burning of fossil fuels began about 200 years ago. Note the ‘spike’ on the right at year ‘0’ Source: Nasa.
Analysis of air trapped in ice cores shows that over the past 800,000 years the normal concentration of CO2 in the atmosphere varies between 170 parts per million (ppm) during cold periods (so called Ice Ages) to 260-300 ppm when the planet reaches its warmest. Concentration of CO2 in the atmosphere now stands at over 415 ppm and is continuing to rise at an accelerating rate as we burn ever increasing amounts of fossil fuels.
For well over a century it has been widely known that CO2 absorbs infra-red light reflected from the earths’ surface then re-emits it, much of it back to the surface. The higher the concentration of CO2 in the atmosphere, the warmer the surface temperature gets, a phenomenon known as global warming which has a number of effects including 1. ocean warming, 2. loss of land-based ice and permafrost, 3. climate change which becomes less predictable and 4. sea level rise. Below is an outline of these effects.
1. Ocean Warming
Most of the additional heat generated by rising levels of CO2 in the atmosphere is absorbed by the oceans. As a result, sea surface temperature is rising and already causing:
Thermal Expansion: As its temperature increases, seawater expands, contributing to sea level rise, changes in ocean circulation and higher seabed water temperature which may be damaging and pose the dangers described below:
Coastal Erosion: Rise in sea level, combined with other factors such as stronger wind events and loss of natural barriers protecting the coastline, result in increased coastal erosion endangering infrastructure, buildings and other facilities located in close proximity to the coastline.
Arctic Erosion: The Arctic ocean is warming, resulting in stronger storm activity and reduced sea ice formation, both contributing to erosion of coastlines hitherto kept stable by permafrost and sea ice reducing wave action. This causes increased exposure and thawing of methane (CH4) bearing sediments and yedoma resulting in emission of this gas and its oxidation to CO2, contributing to its rising presence in the atmosphere and further global warming.
Warmer bottom water: This is accelerating melting of ice enabling faster flow from glaciers discharging to the oceans and erosion of the marine ice sheet covering the West Antarctic archipelago – both causing sea level rise to accelerate and reducing stability of the ice sheet.
Warming seawater, particularly where shallow such as that covering the East Siberian Arctic Shelf, causes thawing of permafrost sediments containing CH4, which is being released directly to the atmosphere, contributing to accelerated global warming.
Fig 2. Before and After. When corals are stressed by temperature they eject algae from their tissues, which give them their colour and die, losing the numerous varieties of fish which depend on them. Source: Environments in Danger.
Coral Die-off: Reefs comprise a great variety of corals often growing in relatively shallow water. Coral reefs are weakened by human pollution making them susceptible to predation but are severely stressed or killed en masse by seawater temperature rising by 2C or more for 6-10 weeks. Their loss exposes adjacent coastlines, often low-lying, to erosion and flooding, destroys fish habitat and reduces fish catch for human consumption.
2.Ice Loss
Mountain glaciers store water which flows into rivers on which human populations depend for potable water, irrigation, food production, transport and generating energy, often in areas of dense population. These glaciers are storing less water and melting more rapidly so that in the future sufficient water may not be available for an expanding human population and its increasing demand for food and potable water.
Permafrost: Vast areas of land in the Arctic contain partly decomposed biota, sediments containing CH4 produced from biota decomposition and yedoma. These lands are permanently frozen but global warming produces surface temperatures which result in it melting more rapidly and to greater depth. As it melts, it exposes biota which thaws, resuming decomposition and producing CH4 much of which is converted to CO2 through oxidation by methantrophic bacteria, then emitted to the atmosphere.
As permafrost melts the land subsides and becomes covered, in shallow water creating anoxic conditions in which methanotrophs are not active and this results in CH4 from decaying biota and thawing yedoma being released to the atmosphere. CH4 and CO2 emitted from permafrost land thawing accelerate global warming. These emissions are already occurring and can not be safely controlled by human intervention.
Land Subsidence: Buildings and infrastructure built on permanently frozen land, particularly in Russia and Alaska, is put at risk when warming surface temperature causes permafrost to thaw and the land to subside. At risk are transport infrastructure, electricity supply, water and sewage mains, oil and gas pipelines and buildings and bridges – even entire cities. Land subsidence is likely to cause damage to the environment – eg. spills from ruptured pipelines. It may prove so costly to repair damage caused by subsidence as to force asset abandonment.
Fig. 3. River flowing on surface of Greenland Ice Sheet into a moulin reaching the ice sheet base. Note discolouration of ice due to aerosol deposits of soot originating from forest and tundra fires, reducing albedo and causing faster ice melt. Credit: Adam Scott Images.
Polar Ice Sheets: Global warming causes the surface of the Greenland Ice Sheet to melt more rapidly, resulting in rivers flowing on its surface, terminating in moulins through which they drain to bedrock. This intensely cold water lubricates the underside of the ice-sheet making it more mobile, before draining into the North Atlantic where it contributes to disruption of overturning circulation and flow of the Gulf Stream.
Ice Melt: Disruption of overturning circulation traps warmer water on the seabed causing the West Antarctic marine ice sheet to melt at its base, contributing to its instability. Warm seawater penetrates polar glaciers eroding ice blockages, enabling glaciers to discharge ice at faster rates resulting in ice sheets becoming less stable, as evidenced in Greenland and West Antarctica. This contributes to faster sea level rise which increases the risk of coastal erosion and flooding.
3. Climate Change
The temperature of the troposphere is now slightly under 1°C above the pre-industrial and is continuing to rise due to increasing emission of greenhouse gasses. This warming is characterised by less predictable, increasingly severe weather events, which include the following:
Temperatures: temperature extremes are setting new record highs and fewer days of extreme cold, though these do occur in the northern hemisphere due to distortion of the polar vortex.
Droughts: affecting farmland and habitat are becoming longer lasting – in many cases lasting over 5 years and reducing river flows.
Evaporation: Increased evaporation of water from soil and lakes occurs because the troposphere is getting warmer and able to hold more water in the form of vapour.
Wind Events such as cyclones and tornados may be less frequent but are more powerful and destructive, their strength increased by rising sea surface temperature.
Rainfall: In some areas rainfall has become less frequent but heavier and of longer duration, while hail storms have become more severe, often with larger hail stones.
On-going global warming will cause these events to become more frequent, last longer and become more severe. Alone or in combination they will continue to cause increasing damage to the environment in the following ways:
Rising temperatures are the principal cause of coral reefs dying, the loss of fish habitat and the protection they provide to low-lying coastal land from erosion by ocean wave action, making them vulnerable to flooding. On-shore temperature extremes are already setting new record highs resulting in declining food production and premature deaths.
Droughts and evaporation of surface water produce similar effects, converting some food bowls to dust bowls, increasing the rate of desertification and killing flora and fauna. Droughts in some parts of Australia have lasted over 8 years, causing rivers to run dry, preventing crop sowing, forcing destocking and overland transport of water to enable survival of town populations.
Fig. 4. Wildfires are becoming larger, more difficult to control or uncontrollable. Damage and destruction of property by wildfires is increasingly expensive with insured losses of 2018 California fires estimated to exceed $10 billion.
Combined, these events result in ferocious bushfires which are increasingly difficult to control, causing huge losses of trees, vegetation, fauna and property – including livestock – all becoming more and more costly to replace, more often forcing abandonment. They also enable pathogens and pests such as mountain pine beetles to invade and kill millions of trees and the spread of vectors carrying human diseases into areas hitherto free of them.
Wind events, often accompanied by heavy rainfall, are becoming more frequent and often result in flooding, loss of human life, damage to property, the environment and crop losses. They produce tidal surges which erode coastlines and flood low lying land.
4. Sea Level Rise
We know that thermal expansion caused by ocean warming and loss of mass from ice sheets and glaciers are the primary causes of sea level rise. Less certain is the speed with which these causes take effect.
Many climate scientists specialising in this area, notably those contributing to IPCC Assessment Reports, are of the view that these are relatively slow processes indicating sea level rise of 0.52-0.98 metres by 2100. Others, including leading specialists in this field, point to evidence showing more rapid loss of ice, producing much faster, multi-metre sea level riseover the same period because of accelerating loss of mass from both the West Antarctic and Greenland ice caps, primarily as a result of increased glacier discharge rates.
Many of the worlds’ cities are located on low coastal land which is very vulnerable to a multi-metre rise in sea level. Australia’s Gold Coast with hundreds of kilometres of canals connected to the sea, Miami in Florida, even mega cities such as Shanghai would sustain heavy damage from sea level rise. Island nations such as Kiribati and the Maldives would be flooded, forcing abandonment. A rise of at least 2 metres is now thought possible by 2100.
World-wide the value of coastal property is likely plummet by hundreds of millions of dollars since there is no protection from rising seas or the increasingly severe storms which they will produce. Several hundred million people may have to retreat from coastal areas threatened by rising sea level this century.
Conclusions
For more than fifty years, climate scientists have warned that continued emission of greenhouse gasses into the atmosphere, particularly CO2, would result in climate change and if average global temperature rises by more than 1.5°C. above pre-industrial levels, those changes would be dangerous. If average global temperature rises by more than 2°C climate changes could become catastrophic, threatening most life on the planet. If we continue to ignore these warnings, we do so at our peril. In practice we have ignored them.
There is only one way of averting the outcomes described above and that is by stopping all use of fossil fuels over the next 10-20 years, improving the ability of natural carbon sinks and new technology to absorb CO2 from the atmosphere. Transition to a decarbonised economy can be achieved within this time frame and, in the process, renewable energy required by the human population could become unlimited in its availability, rather than a constraint on innovation.
There is a price to pay for achieving this. The price is to reduce demand for fossil fuels to meet our energy needs and replace them with renewable energy. Reduction in demand for fossil fuels will result in shut-down of oil fields and refineries, closure of coal mines and stopping production and use of gas over the next 20 years. We have long known the inevitability of these outcomes and the need to ensure they are achieved in a planned, orderly way, involving retraining and re-employment of those currently engaged in them.
Too higher price to pay? Not when compared with the alternative which is to resist change and, in the interests of maximising profit, continue to move far too slowly to avert increasingly dangerous outcomes. Young people rightly protest against this and those responsible for killing flora and fauna (which includes humans), destroying their habitat and giving impetus to the 6thmass extinction now in progress.
This is a nice concise summary of all the important points. It might almost be an idea to put it under "IPCC facts " or something similar so there is a permanent link to it.
Another reason young people are becoming vociferous is perhaps because they see the double standards of adults who say there is a problem yet do nothing. It may also be because young people get some of the science at school, and are also not deluged with denialists rhetoric as much as adults are.
However one quibble. I'm not sure that climate change has become more political and partisan because the results of climate change are becoming more obvious. If it is I think you need to explain how, maybe I'm missing the point. If anything increasingly obvious bad weather may make it less political and partisan as it becomes harder to deny.
Climate change is more likely becoming more political as a result of America's culture wars that have complicated causes and have gained a life of their own getting worse and worse for no logical reason. An analogy might be the way WW1 developed and spiralled out of control, in an unstoppable sort of way.
It's unfortunate that the IPCC reports have not at least mentioned the possibility of multi metre sea level rise by 2100. If they have it's certainly buried away in the fine print.
Climate change is already becoming catastrophic and everywhere researchers are looking life is being threatened far more than was thought even a few years ago.
Many insect populations are in critical decline, the same goes for avian populations and many others. It's not just climate change that is doing this, but global industrial society overall where there is no long range planning as short term profit making drives almost all economic activity.
I also seriously question that relying on low energy density "green" energy technology is going to prevent a catastrophic collapse of the biosphere in the near future.
They would need to be implemented on a vast scale to replace all fossil fuels and that would require equally vast resource extraction, transportation, manufacturing and construction.
There's only one shot to avoid a systemic collapse now is my take on this.
Nuclear power and one specific type, the molten salt fast reactor running the thorium fuel cycle.
Molten Salt Fast Reactor
If green renewable energy production can take up to 1,000 times the space - with all the attendant resouces to build it - of fossil fuels;
Renewable energy sources can take up to 1000 times more space than fossil fuels
And in turn nuclear power can have millions of times the energy denisty of fossil fuels.
Energy Density Comparison
Then that gives us an energy density of nuclear power several billions times that of green renewables. And where a lump of thorium that can fit in your hand will provide all the energy you need in a lifetime, the mass needed to provide energy from low density renewables - including the space dedicated to it - would be many tons that would crush you.
My question is, do we really have the resources and time to be so idealistic about energy production when the situation is now so critical. And when there are serious question about the actual physical response to ionizing radaition which is the main hazard with nuclear power.
If for instance if ionizing radiation may actually have a beneficial effect on people exposed to slightly higher levels of background radiation as the Nuclear Shipyard Workers study indicated.
Nuclear shipyard worker study (1980–1988): a large cohort exposed to low-dose-rate gamma radiation
And new research seems to indicate that within certain thresholds ionizing radiation isn't just harmless to people but it may in fact be essential to the normal functioning of our cells.
Is Radiation Necessary For Life?
I think it's entirely possible we have been avoiding the solution to many of our problems for decades for fear of something that has never been the risk it has been presented as since the mid 1950s that some researchers consider a scientific fraud for political purposes.
On the origins of the linear no-threshold (LNT) dogma by means of untruths, artful dodges and blind faith.
Just my thoughts, we can keep running in fear from something that always has been and always will be an intrinsic part of our being;
Are Our Bodies Radioactive?
Or embrace what is likely our last shot at salvation at a species level. As I said, given the scale needed to implement low density energy production with the misconception it is clean when a vast amount of resources must go into manufacturing it and an equally vast amount of space must be taken up by it, I think going completely "green" is just as dangerous as fossil fuels energy production.
Doug_C @2, I agree with your first two paragraphs. The main issue with nuclear power is the economics. This is because our civilsation works on what is the most economic option to generate a desired outcome, and right now wind power is lower cost than nuclear power, and solar power is about the same (according to Lazard's analysis), so generators tend to prefer renewable energy, especially given the large scale of nuclear projects and complicated approval procedures.
The space taken up by renewable energy is just not significant, because solar power panels tends to be on building's roofs and can be deployed in waste land and in deserts, and wind tower pylons sit on farming land not taking up significant space.
Of course safety is a big concern as well as economics, and I recall reading something that suggested that radiation below a certain level is harmless and that the relationship is not linear. But nuclear accidents are a nightmare and very costly to clean up.
Resources are an issue to consider, but the world is not about to run out of important minerals not for many centuries yet, and even if we were things won't slow down because capitalism is like a voracious machine. Imho our main hope is smaller global population.
Given nuclear power is not exactly low cost it must use plenty of materials and (fossil fuel) energy in construction and mining those materials, so I'm not convinced its particularly low carbon in terms of manufacturing. Of course I do realise some of the costs are in scarce metals. But do you have some hard data comparisons on carbon content in manufacturing between nuclear power and the other options?
If thorium reactors become economic, and can be shown to have low carbon in the manufacturing process, great, I have no objection. Until then we have to work with what is plausible in the real world.
nigelj @3
The scale of it just doesn't seem right for low density renewables. If as the data says nuclear power has several billion times the energy density of energy sources such as solar and wind power and it would take about 15,000 1,000 MW nuclear power plants to totally replace fossil fuels, wouldn't that require several trillion comparable renewable energy sources.
We're talking about a huge amount of energy needed to replace all fossil fuels and finite resources, space and time to do it.
As for nuclear power, my point about the actual biological response to ionizing radiation in most dose rates anyone will be exposed to is that the requirements placed on nuclear power for nearly zero levels of emissions are part of what makes it so costly.
And we couldn't go with "conventional" light water reactors now anyway as a replacement to fossil fuels because the industrial base to build the thousands of massive stainless steel primary containment vessels simply doesn't exist.
What is being proposed by some is the molten salt fast reactor concept that does away with the need for massively strong primary pressure reactor vessels and the need for equally massive secondary containment in the chance there could be a catastrophic loss of radioactive collant.
Why the molten salt fast reactor (MSFR) is the “best” Gen IV reactor
With a molten salt reactor your primary containment is chenical as the fissile material is held in solution in the molten salt. The reactor is not under pressure and there is no chance of a melt down. The core is already molten.
We know the concept works as ORNL ran one for several years in the 1960s and worked out much of the chemistry and materials issues.
Molten-Salt Reactor Experiment
A fast molten salt reactor simplifies the concept as it does away with the need for a core graphite moderator that needs to be changed every four years and simplifies fuel reprocessing.
They can also be built in modular design so you can have 300 MW moduls that can be conbimed to produce larger plants giving flexibility to implementation.
Waste is also greatly decreased with MSFRs as they produce a fraction of transuranics(TRUs) that are such an issue with light water reactors that use solid fuel rods that break down from exposure to heat and neutron bombardment in the core and become less stable due to the buildup of fission products over time.
You get an almost complete burnup with a molten salt reactor so almost all your waste is short lived fission products that can be safely stored onsite as has been done for decades with the current light water reactors.
Molten salt reactors also use a gas parging system that makes it possible to pull fission products out of the core salt unde4r operation that might interfer with the stable running of the reactor and some are highly valuable for things like nuclear medicine like Moly-99 used in imaging, Iodine-131 and bismuth-213 used in cancer treatment.
MSFRs also produce small amounts of Pu-238 used as a power source for deep space mission and ample xenon with is fuel for ion rockets in the space sector. They also produce noble metals like gold, silver and platinum.
There's so many advantages to MSFRs and once the infrastructure is created to begin large scale production the cost would be a fraction of what nuclear power now costs.
I think it's the way to go for many reasons.
Another is running thorium in molten salt reactors also produces little fissile materials that can be used in weapons manufacture. It is nearly a 1-to-1 ration of fissile material undergoing reaction in the core to thorium in the blanket being converted to U-233 by the neutral flux being produced by the reactor. Take out the new U-233 and the reactor stops running for lack of replacement fissile material.
As I said it's a question of scale. And if thousands of reactors in the 1,000 MW range are required to phase out all fossil fuels and nuclear power has billions of times greater energy density than renewables then a comparable renewables energy model will require trillions of comparable facilities dispersed over large areas of the Earth.
It's still possible to implement solar, wind, geothermal, tidal, etc... energy under a nuclear power replacement regime, it just make it so the scale of that part of the model can be greatly reduced.
As for economics, we will be creating an entirely new economic model to reflect the new energy model. At its basis any economic model must include a viable biosphere to take place in. And then build out from there.
And the best way to acheive that is to use the most efficient sources of energy that use the least amount of finite resources and take up the minimum amount of space that otherwise could be part of a viable ecosystem with sufficient biodiversity indefinitely.
Nuclear power in the form described above would seem to fit that bill far better than low density renewables on the face of it.
Be interested to see that take others have on this.
Doug @4, I know what you are saying: A single reactor building producing 1000 mwatt intuitively seems to use less materials than a big solar or wind farm of equivalent output. However it would be useful to see a hard data comparison, because appearances can sometimes be deceiving. And the sciency types on this website would rightly insist on it. I do think it would be a good argument in favour of nuclear power if you are correct, so its interesting.
Molten salt reactors are still somewhat experimental. I agree they have many advantages, although one sticking point is the ability to produde high grade nuclear weapons materials. Its this sort of thing that is slowing development down. In the meantime we obviously have to build what is feasible like solar and wind power. We are lucky we have geothermal power.
This is an excellent summary of the symptoms of the illness.
However, for remedial action to be taken, the question to be answered is "What should we do?". Answers include "Reduce CO2 in the atmosphere", "Eliminate emissions of CO2", "Eliminate emissions of methane". But, these are too general to lead to action.
The questions in turn give rise to "How?" For example, "How can CO2 in the atmosphere be reduced?" with answers such as "Carbon sink", Carbon capture and storage", "Filter CO2 and water from the air and convert to oil" (https://www.nature.com/articles/s41467-019-09685-x), "Remove carbon from hydrocarbons before burning" (https://www.newscientist.com/article/mg23230940-200-crack-methane-for-fossil-fuels-without-tears/). Each of these have advantages and disadvantages and give rise to lower level questions.
We must carry such analyses through to actions that people can see make sense. "Climate Emergency" by itself is so abstract and frightening.
nigelj @5
That is what is needed. A comprehensive breakdown comparing the relative resources that go into making and running a 1,000 MW MSFR nuclear power plant as opposed to how many wind turbines, PV solar panels, tidal generators, etc... are needed to provide the same energy production and what overall ecological impact they both have.
As for weapons proliferation which is a serious concern, the thorium fuel cycle in molten salt reactors effectively addresses this concern. Once the reactor is in operation it needs new fissile material added to it as the initial charge of either U-235 or U-233 is used up by fission. The reactor core would have a blanket loop surrounding it of molten salt with the thorium in solution. The neutron flux from the core fission reaction provides just enough neutrons to keep the core fission reaction going and breed new fuel from transmuted thorium in the blanket, it's a little over a 1-to-1 ratio.
If you start taking out the new U-233 from the Th-232 that has just been transmuted then there is no new fuel to keep the molten salt reactor in operation. Th-232 is also seven neutron captures away from weapons grade Pu-239 while U-238 is only one neutron capture away making uranium the preferred fuel cycle for weapons creation.
A MSFR would be producing about 0.159 kgs of Pu-239 a year while a light water reactor would produce about 110 kgs in that same time period.
Why the molten salt fast reactor (MSFR) is the “best” Gen IV reactor
We are suffering from institutional cognitive dissonance here in Canada.
The newly elected Alberta government where oil and gas production is considered sacrosanct has declared an intention to create a $30 million "war room" to attack anyone threatening the fossil fuel sector in Canada.
Environmental groups shrug off Jason Kenney's 'war room' threat
While significant regions of Alberta are currently under emergency measures due to climate change driven wildfires. They are sending firefighters from across Canada to deal with a climate change driven emergency in Alberta that will only get worse as industry and government there do almost anything to protect the oil and gas sector.
B.C. sending more firefighters to help battle Alberta wildfires
This is highly irrational as the Alberta government has been threatening BC economic interests for several years over the resistance to the Trans Mountain pipeline expansion plan.
UCP poised for battle with B.C. over Trans Mountain pipeline expansion
So while BC is treated as the enemy when we don't bow to pressure to not just maintain current levels of fossil fuel use but expand them, when climate change emergencies that have been predicted for decades are in fact now happening we are also expected to respond to the provinces that are driving this sector over all reason.
Federally the Green Party leader of Canada has declared she also supports fossil fuel use for decades as long as we don't import any of it.
Elizabeth May wants to only use Canadian oil — a plan Quebec's Green Party leader can't support
It's not like there isn't awareness at the highest levels of the crucial need to phase out fossil fuels, the Canadian government signed the 1997 Kyoto Protocol to phase out fossil fuels and then again in Paris in 2016.
But when it comes time to actually enact policy to do this, government after government balks and the private sector pretends there is no crisis.
While investment in alternative energy has been very low in Canada for years, investment in fossil fuels is still massive here.
Canada’s major banks have financed $464 billion worth of fossil fuel projects since 2016.
What do we as citizens do when the private sector that obviously wants oil and gas use no matter the catastrophic impacts uses part of the proceeds of their business to effectively control policy.
Life is dying on Earth while conditions for people are becoming very dangerous as well as with some of the deadly wildfires in California, Australia and other places. We are lucky we have not lost people here in BC with how critical our wildfire situation has become. In a month or so we probably won't have the firefighting resources to share with other regions when our fires start catching.
Anyone who is still claiming this make sense in any context is totally delusional, we get off all these highly polluting fossil fuels as fast as possible or we in fact do face the horrific prospect of an unlivable world in what is in geological time the blink of an eye.
If we are going to call the recent icy period an Ice Age, which extended between the Eemian interglacial some 125 thousand years ago and the present Holocene interglacial then what are we going to call the 2.75 million year period in which there have been more or less 40 cycles between ice and not much ice. I don't care what we use as long as we use it consistently. It is not just semantics. Some folks, even a program on National Geographic, suggested that the fauna of North America died out because of the climate change at the beginning of the present Holocene interglacial. Nonsense. These animals had survived multiple cycles in fine fettle. The only difference was the advent of man into the Americas. Terminology, especially in science, is important.
william @9
Correlation does not equal causation. Just because humans were present in the Americas when the megafauna went extinct is not evidence that they were the cause of this extinction.
What Killed the Great Beasts of North America?
"The idea that humans wiped out North America’s giant mammals, or megafauna, is known as the “overkill hypothesis.” First proposed by geoscientist Paul Martin more than 40 years ago, it was inspired in part by advances in radiocarbon dating, which seemed to indicate an overlap between the arrival of the first humans in North America and the demise of the great mammals. But over the years, a number of archaeologists have challenged the idea on several grounds. For example, some researchers have argued that out of 36 animals that went extinct, only two—the mammoth and the mastodon—show clear signs of having been hunted, such as cuts on their bones made by stone tools. Others have pointed to correlations between the timing of the extinctions and dramatic fluctuations in temperatures as the last ice age came to a halting close."
If early human arrivals in the Americas killed off some of the megafauna why did they then stop and allow massive numbers of other quite large species to remain like the Bison, Grizzly Bear, Musk Ox and others.
The rapid fluctuations in climate at the end of the last glaciation period and the extinction of species that lost their associated habitats is likely evidence of how dangerous climate change can be to life.
@Nigelj, @Dougc:
Comparison of the GHG footprint of several generation techniques can be found en.wikipedia.org/wiki/Carbon_footprint. Nuclear at 60~65 gCO2-eq/kWh, wind power at 21 and PV solar at 106. I've seen other studies setting Nuclear at 24~85 (mining exclude/included) Windpower 8~30 (recycled-new) and PV 20~80 (production techniques, mining) and also biomass IEA report with carbon negative outcome of -9 g CO2-eq/kWh, presumably from sustainable forest with more growth than extraction. As a note: LCA includes demolition costs of the installation after it's lifetime. Now I have seen that for PV, Wind power and biomass powerplants all on lifetime expectancies of 20~30 years including derating. For coal fired plants that period is taken to be 50 years. There is no derating for coal fired as that is maintained to be at top capacity. I wonder if that is realistic. For NPP the minimum I've found is 60 years and very wide margin for the costs: not enough experience. I would say take the costs of a Fukushima till now and you will not make a big mistake: even in case a NPP is shutdown, it will take a 35 years before one can think of taking it down. And all used fuel in place will be active for another 100 years.
Ger @11
That's probably for the current light water reactors, I'd be really interested to see what the numbers are with MSFRs when they finally get one up and running. With only a fraction of the concrete needed for secondary containment with a light water reactor they should sharply cut the initial carbon output and with the much higher fuel efficiency and greatly reduced waste stream the operational and end of life costs and footprint are probably going to be much smaller.
Instead of large batches of degrading fuel rods being removed every few years as with light water reactors they would be pulling fission products constantly out of solution from an MSFR and either storing them onsite or selling some of the fission products such as medical radioisotopes or xenon to the aerospace sector where it is used as ion rocket fuel. And with very little TRUs the long term waste costs and footprint is also going to be a fraction of current costs with LWRs.
One thing that will be an issue is the meter thick steel neutron reflectors that after several decades of operation are going to be a radiological hazard for decades as cobalt-60 has a half life of 5.6 years.
I also think it is far past the time to keep letting free market forces determine the energy model we use. From all the evidence if energy policy isn't controlled and guided at a global level then we face catastrophic conditions on Earth that make free market economics or any thing else human related moot. Because we keep doing what we're doing much longer then there will be no people left.
I think there need to be hard targets imposed on the energy market that have a 50% reduction in fossil fuels use by 2030 and a 100% by 2050.
This would require somthing like much safer and hihgly efficient Gen IV nuclear power to be implemented on a large scale in conjunction with renewable energy.
William @9,
Picking up on your "what are we going to call the 2.75 million year period" question, I'm not sure what prompted it. Your preceeding sentences sound perhaps a bit accusative and if so, perhaps you mis-read the OP that actually mentioned "cold periods (so called Ice Ages)" over the past 800,000 years.
The period prior to the Holocene and back +2½million years does have a name, the Pleistocene and it is a period of 'ices ages' and 'interglacials'. The characteristic that makes it different to the periods before was the preceeding formation of the Panama Ismuth and the subsequent arrival of (or perhaps the more extensive arrival which Knies et al 2014[PDF] appears to show) permanent polar ice in the Northern Hemesphere, particularly the Arctic Sea Ice. In light of the permanence of NH ice through the Pleistocene (it apparently didn't disappear in the Eemian, for instance see Stein et al 2017) I think the arrival of ice-free Arctic summers for the first time in millions of years is a strong scientific message that has yet to be wielded properly.
Doug_C @ 8: Speaking of cognitive dissonance, let's not omit BC's continued enthusiasm for coal mining and export: https://nationalpost.com/news/politics/yes-anti-pipeline-vancouver-really-is-north-americas-largest-exporter-of-coal
ianw01 @15
It's not good here.
Although we've had a carbon tax for over a decade in BC, it is next meaningless when the government gives exemptions to some of the largest CO2 emitters.
John Horgan offers tax break incentives to $40B Kitimat LNG project
How exactly are we addressing fossil fuel driven climate change when official policy at the highest level is effectively paving the way for decades more fossil fuel extraction and burning at a massive level.
In BC it gets ever worse than that, the Site C dam has been controversial for decades yet with no real approval process taken a massive hydro-electric project that will cost the people of BC over $10 billion will be built in the middle of the Montney gas formation that will be used to power gas gracking for decades.
This will produce trillions of cubic meters of gas and leak large amounts of methane into the atmosphere. Fracking itself endangers ground water and destabilizes the bedrock over large areas producing greatly increased sesmic activity.
Then is no rationality at all in energy policy in BC or anywhere in Canada. The entire nation has become captured by the fossil fuel sector. Instead of debating how to get off all fossil fuels as quickly as possible we're fighting over where to ram new oil and gas pipelines through and even "Green" leaders are claiming Canada must utilize our fossilf fuel reserves for decades more.
Which was the same argument decades ago when climate change was first recognized as an existential threat. The claim here is that because Canada is only responsible for about 2% of the world's CO2 emission we can keep doing what we want and no one will notice.
But Canada makes up about 1% of the global population so on an individual level Canadians are some of the largest emitters of carbon dioxide.
We have a lot of room to change and little political will to actually do so despite all the virtue-signalling of Justin Trudeau who said this at the Paris climate change summit in 2015.
'Canada is back, my friends. Canada is back, and here to help,' prime minister tells delegates
He then went to an oil and gas symposium in Houston Texas and said this to oil execs.
No country would find 173 billion barrels of oil in the ground and just leave them there,
I'm ashamed to say that Canada as a nation is not going to be part of a solution to this existential crisis we have forced ourselves into by blind greed.
DougC,
Sorry I am late to your party, I was out of town.
I seem to recall you posting pro nuclear propaganda a few month ago here. Once again you are posting off topic so I cannot reread our previous discussion. You seem to me to be repeating yourself which is prohibited by the comments policy. Unfortunately, no nuclear supporters are willing to write an OP in support of nuclear so you have to post off topic.
Your posts contain too much that is patently false to address all your issues so I will summarize.
Your discussion of nuclear does not include the vast areas needed as safety buffers around nuclear plants. It has been calculated that as much as 22 km2 is required for each nuclear plant, far greater than your simple assertions.
Your assertions that energy density is required is simply false. It has been widely demonstrated Jacobson 2018, Connolly et al 2016 , Aghahosseai et al 2019 (Aghahosseai has at least 20 references to other studies that provide 100% power using renewable energy) that renewable wind and solar power can easily power the entire economy for the entire world. By contrast, Abbott 2012 demonstrated that the rare metals required for nuclear power stations do not exist. Dittmar 2012, a widely respected nuclear physicist, states that any money spent on nuclear, including research, is wasted and should be spent on renewable energy instead.
I am sick of your claims about radiation for these reasons:
Your reference claims 10,000-30,000 reactors are needed to power the world. Your number of 15,000 is low. You should use at least 20,000. Abbott 2012 gives 13 reasons why nuclear can never be built out to this extent. Please say where you would locate the 4,000 reactors needed for the USA alone.
Your statement "wouldn't that require several trillion comparable renewable energy sources." is simply uninformed BS. Jacobson 2018 calculates about 4 million total power systems, mostly wind and solar and an additional about 1 billion solar panels on houses and buildings. Your estimate of "trillions" is off by a factor of millions and is deliberately false or deliberately uninformed. Read the background so that you do not make these gross errors.
Why should I believe anything you say when you make gross, uninformed errors like this??
The French Nuclear regulatory agency has stated that generation 4 reactors are no safer than current designs. Your claims of safety are simply industry propaganda. This applies to your claims of less expensive reactor enclosures.
Alloys that can withstand the intensive neutron flux and the extraordinary corrosive environment of a liquid reactor for 40 years have not been identified. The ability to clean up the waste stream from the liquid fuel has not been demonstrated at industrial scale. Utill materials are found and techniques demonstrated the reactors cannot be constructed. By the time these are demonstrated it will be too late. We must build out non-carbon power now.
Nuclear proponents complained about materials needed to build out renewable energy 10 years ago. Jacobson 2011 details all the materials needed to power the entire world all power and showed that all materials except for rare earth elements needed for wind turbines exist. Since then the turbines have been redesigned so they do not use rare earth elements.
By contrast, Abbott 2012 shows that rare metals needed for construction of nuclear power plants do not exist. The nuclear industry has not challenged his papers so we must assume Abbott is correct.
We cannot do the materials comparison you demand because the data for nuclear plants does not exist to compare to the readily available data for renewables.
I become angry when nuclear supporters make these fatuitous arguments and parrot industry propaganda unsupported by data. Serious posters then doubt that renewable energy can generate enough energy when many peer reviewed papers clearly demonstrate renewable energy can generate enough power. This is exactly the same technique fossil companies use to sow doubt in all efforts to deal with AGW.
michael sweet
Abbot did a demostration paper it was not meant to be taken too literally, for example he mentions the limited abundance of halfnium as a control (which is limited to military reactors) civilian reactors use boron and some gadolinium which are far more abundant than halnium, a completly irrelevant FACT that you should know.
please put out the abbott reference so that others can judge it
[PS] The Abbott paper can be found here. What you mean by "demonstration" paper is unclear nor why you infer it was not meant to be taken too literally.
Michael,
a Curie of high energy beta radiation, could you enlighten us at to what isotope do you refer to?
Barry, you say that boron and gadolinium are "far more abundant" than hafnium" . A quick look at "abundance of earths elements in earths crust" on wikipedia shows that gadolinium and boron are about twice to three times more abundant than hafnium. I would not necessarily call that far more abundant, and whether they are in accessible sorts of places is another question. You also don't offer proof that boron and gadolinium are "abundant enough" to provide enough materials for a mass roll out of nuclear reactors ( at affordable cost obviously). It would need an in depth analysis of known reserves, and their accessibility and reactor requirements and you offer none of this.
I think the point is we could discuss this it will probably go around in circles. If people object to Abbot's published research, and want to be taken seriously they should a) publish a proper peer reviewed opposing point of view or b) take up the offer made to submit a proper article to this website which should include references to source materials. The fact they do neither does not inspire one with great confidence.
And I'm told a lot of rare earth materials are in China who could in theory restrict the supply. No doubt America has rare earths but it takes a very, very long time to develop new mines so this is not helpful for the climate problem.
I have no firm objection to nuclear power, and no technical expertise but I do know the present water cooled technology has a lot of problems and new technology like molten salt lithium reactors remains experimental and is slow to develop, so our best bet in the meantime looks to be renewables.
[PS] Sigh, this is now way off-topic. Nuclear debates tend to derail other discussions and this one looks to be no exception. We have asked for nuclear proponents to write a guest post where such discussions could continue (which would need to discuss Abbott with peer-reviewed references) but so far no takers. If Doug C or barry want to volunteer then go for it.
Meanwhile I suggest that nuclear power debates be taken to another more suitable forum. Bravenewclimate would seem to a more appropriate place.
Barry:
The moderator has asked that the discussion be taken to other locations. I will not go, it is a waste of my time. I think the regular readers of this forum have already made up their minds one way or another. My experience is these discussions rarely change minds.
Abbott 2012 was published in the Bulletin of Atomic Scientists by invitation. You cannot be serious in your comments.
The isotope was Yttrium-90. We were making anti-cancer treatments. Are you knowledgable enough that this makes a difference to you??
Barry,
Another poster recommended the Moltex reactor for the future. From their site:
"The molten fluoride coolant salt in the SSR contains hafnium"
Hafnium is used in critical locations of civilian plants. If you do not know the FACTS you look stupid lecturing others who do. Read the background information.;
moderato, thanks for the link, I is a long time since i read the paper.
i hope that this will answer your question
nigel, your figures on the relative abundances of halnium are misleading.
you have used crustal concentrations by mass, and wikipedia gives typically 2 to 3 times highe amount
of boron than halfnium.
however for nuclear absorption use one should use mol, since it is by atom that these materials absorb neutrons
so this brings the factor of 3 up by 178/11 = 48.
Coupled with the fact that boron is mainly found in lake deposits not in the crust makes this very irrelevant, on top of this there is avast amount of boron in the ocean some 4.5 -4.8 mg/kg which is readily available
I suggestquantity is easily extractable and exceeds the born quantity in the crust so there is a factor of 100 more for the abundance of boron assuming every drop of halfnium is extracted from the crust
so Boron is far more abundant than halfnium, and can be readily seperated after use, the unreacted isotope slvaged by distillation and so will become non radioactive.
as for hafnium in civilian reactors I stand by it that it is currently not used to any significant extent
The moltex reactor
"Modest funding now will see Moltex through these approval processes,
initially in the UK and Canada, and through to the construction of the first reactor.
Thereafter the market is almost inconceivably large.
Mr Sweet the reactor has not been built! It is a future projection. please do not insult people.
As for Abbotts figure of 20.5 km^2 per reactor, Abbot does not explain the calculation of these figures but his citation does
The originator, Johnson uses US figures, a coutry which has the largest redundant areas for its nuclear facilities nevertherless he states that the
area occupied by nuclear facity and its supprting infrastructure of enrichment, mining and disposal in the states is between 4.9 and 7.9 km^2.
Now a facility can have several reactor typically nowerdays say 6 giving a reactor area of 4.9/6 = 0.8166 km^2 a long way from Abbots 20.5 km^3 a factor of 25!
Abbott inflated his figure to include the us buffer zone which can still be used for agriculture or say a solar farm, which Abbott claims is n either or not both!
Please treat Abbotts figures with great caution . It is as I said and he has communicated to me only a demonstration
[PS] thank you but no more nuclear energy discussions on this topic. Hopefully we will have a more appropriate place for those interested in the subject in the future.