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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Suggested supplemental reading:

Climate science’s official text is outdated. Here’s what it’s missing. by Eric Holthaus, Grist, Mar 22, 2018

Anne-Marie Blackburn at 06:25 AM on 30 March 2018

Arctic was warmer in 1940

Hello Napin, welcome to Skeptical Science! Your question is an interesting and important one because what we choose to do as a society depends on our understanding of the problem we’re facing. If we don’t understand the problem properly we might make decisions that fail to address it. So how can we make sure the information we’re given is correct?

One of the first steps we can take is to check the source of the information. In the case of the claim that Arctic temperatures were warmer in the 1940s, the author is Christopher Monckton and his article was published on the Science and Public Policy Institute (SPPI) website. Christopher Monckton is not a climate scientist and the SPPI is not a scientific publication. This doesn’t necessarily mean that the information is incorrect but it does mean we have to evaluate his claims carefully. If we look at his graphs on Arctic warming we notice a few things. First, there is no reference given for the graphs so it’s not possible to check whether they’re reliable. Without access to the data so that we can produce our own graph, we can’t say that this graph is accurate.

In the case of the second graph, it seems that Monckton is only looking a small selection of weather stations. It’s hard to tell because he hasn’t provided a reference to the data in question. As Robert writes in his article, Monckton doesn’t seem to an analysis that covers the whole of the Arctic. In other words, Monckton has cherry-picked a few weather stations that support his argument rather than looking at all the evidence. In the case of the third graph Monckton once again fails to provide a reference so we face the same problem as with the two other graphs. Also the graph ends just after the year 2000 so it misses out a lot of the recent warming.

So I think we have good grounds to question Monckton’s claims at this point, especially as no scientific institution agrees with him. But more broadly there are things we can do to protect ourselves against misinformation. This is important because it can help us assess the validity of all claims made about a scientific topic. Skeptical Science has produced an online course which highlights the ways in which misleading arguments are constructed. Once we understand what to look for it becomes easier to spot misinformation. For instance, Monckton implies that since Arctic temperatures have changed naturally in the past, then current warming must also be natural and we don’t need to worry about CO2 emissions. This is not a scientific position. Climate has changed in past because of a number of factors - variations in solar activity, the Earth’s orbit around the sun, volcanic activity, changes in atmospheric composition, including CO2 levels, etc. We can only understand current and future climate change by looking at what’s happening now. Past climate change can help us make predictions about what will happen in the future, but it tells us nothing about the causes of current change.

If you’d like to learn more about the various ways misleading information is used, you might be interested in our online course, which can be found here. Week 1 and Week 6 are particularly useful. Also John Cook and some fellow scientists have published a recent handbook in which you might find useful information. I hope I have answered your question and if there's anything else I can help you with, please let me know.

bruceparker at 05:26 AM on 30 March 2018

Skeptical Science now an Android app

What happened to the app on Google Play?

nigelj at 05:14 AM on 30 March 2018

How could global warming accelerate if CO2 is 'logarithmic'?

Well written comprehensive post quoting many sources, but didn't seem to have one on background information on why CO2 has logarithmic growth.

Alchemyst at 04:35 AM on 30 March 2018

Explainer: The polar vortex, climate change and the ‘Beast from the East’

Daniel Baily at 11 54 16 march

It appears that there is an explanation for the cold winters in western europe and it appars to be linked to sunspots, or their abscence

https://phys.org/news/2011-10-link-solar-winter-weather-revealed.html

Scientists have demonstrated a clear link between the 11-year sun cycle and winter weather over the northern hemisphere for the first time.

They found that low solar activity can contribute to cold winters in the UK, northern Europe and parts of America. But high activity from the sun has the opposite effect.
The study helps explain why the UK has been gripped by such cold winters over the last few years: the sun is just emerging from a so-called solar minimum, when solar activity is at its lowest.
'Our research establishes the link between the solar cycle and winter climate as more than just coincidence,' says Dr Adam Scaife from the UK's Met Office, one of the study's authors.
The findings, published in Nature Geoscience also raise the tantalising possibility that the regularity of the solar cycle might help weathermen predict cold winter weather over the northern hemisphere.
'We've been able to reproduce a consistent climate pattern, confirm how it works, and quantify it using a computer model. This isn't the sole driver of winter climate over our region, but it is a significant factor and understanding it is important for seasonal to decadal forecasting,' says Scaife.
Up until now, researchers have only managed to see a weak link between solar activity and winter weather: when the sun is less active, we're more likely to see weak westerly winds during the winter in the northern hemisphere. This pattern suggests that easterly winds could bring cold weather from the continent to the UK.
But scientists have struggled to incorporate these ultraviolet (UV) signals into climate models.
Now, new satellite measurements from NASA's Solar Radiation and Climate Experiment (SORCE) have revealed that differences in UV light reaching the Earth during the 11-year solar cycle are larger than previously thought. The satellite, launched in 2003, is the first ever to measure solar radiation across the entire UV spectrum.

Read more at: https://phys.org/news/2011-10-link-solar-winter-weather-revealed.html#jCp

william5331 at 04:32 AM on 30 March 2018

How could global warming accelerate if CO2 is 'logarithmic'?

Factor 5 is tipping points. As stated, carbon sinks are expected to take up less Carbon dioxide as they saturate so this will push up atmospheric CO2. Add to this, for instance, the possibility of huge burps of Methane from the various sources of Carbon dioxide clathrate. Despite the short life of Methane in the atmosphere, it could shoot up global warming to a point that the existing sinks loose more of their power to absorb the gas while at the same time pushing us over other tipping points such as a sudden complete melt of Arctic floating ice for a much longer part of the year. We are taking a giant step in to the unknown with our eyes closed.

One Planet Only Forever at 04:09 AM on 30 March 2018

Stop blaming ‘both sides’ for America’s climate failures

People can better appreciate how unhelpful Pinker's "Enlightenment Now" actually is by reading books like Naomi Klein's "No is Not Enough". It has been recommended by many people including Noam Chomsky (a far more relevant judge of what helps raise awareness and better understanding than Bill Gates) whose simply stated evaluation is "Urgent, timely, and necessary".

In "No is Not Enough", the section of Chapter 4 (The Climate Clock Strikes Midnight), titled "What Conservatives Understand about Global Warming - and Liberals don't", includes the following: "... when hard-core conservatives deny climate change, they are not just protecting the trillions in wealth that are threatened by climate action. They are also defending something even more precious to them: an entire ideological project - neoliberalism - which holds that the market is always right, regulation is always wrong, private is good and public is bad, and taxes that support public services are the worst of all."

Pinker may not be a fanatical promoter of neoliberalism. But I do not see him bluntly criticizing the current day threat that its promotion by people calling themselves Conservative is. And he certainly does not appear to tell Conservatives that they need to act aggressively against neoliberals rather than uniting with them (and the less tolerant among us) in the hopes of Winning.

Pinker's presentation of criticisms by Klein and the Kochs of the Washington State Carbon Tax proposal does not distinguish the different motivations of Klein and the Kochs. It is either poorly informed or deliberately misleading.

One Planet Only Forever at 03:13 AM on 30 March 2018

Stop blaming ‘both sides’ for America’s climate failures

I find “Enlightenment Now” to be heavy on sales pitches defending people who have Private Interests that are contrary to more rapidly achieving the Sustainable Development Goals, people inclined to want to believe that 'future generations will figure out amazing solutions to whatever problems current day people create' or 'deny that the systems that have developed create unsustainable and harmful results and need to be corrected'.

The end of chapters that relate to the SDGs consistently make claims that what has developed so far is Good that can be expected to get Better (Feel Good Claims), with implications that the Good and Better are natural expected outcomes of the systems that have developed. The reality is that any Good has actually been 'corrections of identified harmful unsustainable developed activity that occur because of raised public awareness and better understanding of the incorrect popular and profitable developments in the developed socioeconomic-political systems'.

Within those chapters Pinker often criticizes people who try to raise public awareness and better understanding of the harmful unsustainable things that have developed because such 'efforts to better educating of the public' likely upsets people who consider themselves to be Conservative. Making people with Private Interests contrary to achieving the SDGs learn to change their minds is a challenge. Helping enough Other people become more aware and better understanding is a solution.

To be helpful, Pinker could have focused on his linguistics and cognitive specialization to develop and present an evaluation of why misleading marketing in support of Private Interests that are understandably contrary to the achievement of the SGDs are so successful and what can be done about that undeniable developed problem.

Onpimon at 01:40 AM on 30 March 2018

Increasing CO2 has little to no effect

I agree with the statement that CO2 is one of the main driven of climate changes. But it’s not the only one. There are some other things or other gases that can cause climate changes. Actually it’s no matter what can cause climate change more or less we have to prevent it. However, we have to concern on what can cause climate change the most. So, we can find a way to prevent it.

Moderator Response:

[TD] You are correct that there are other drivers of climate change, but human-caused increase of CO2 is the most important cause of the current warming. Please read the post "CO2 Is the Main Driver of Climate Change."

Onpimon at 01:37 AM on 30 March 2018

Was Greenland really green in the past?

Thank you for posting.

I agree with the topic, Greenland used to be green. When Greenland has discovered and named by Erik the Red about 1,000 years ago, it will be different from now. If there is no any evidence that show Greenland was green, he would not name this place as Greenland. The DNA is proof that sometime between 450,000 and 800,000 years ago, much of Greenland was especially green and covered in a boreal forest that was home to alder, spruce and pine trees, as well as insects such as butterflies and beetles (From: https://www.livescience.com/7331-ancient-greenland-green.html). And from the map, like Google map or map in Wikipedia we can see that the edge around Greenland is still green. Greenland ice sheets is between 400,000 and 800,000 years old. So, Greenland today will maybe different from the past. Because of the global warming. Global warming not just changing Greenland, but it affects all over the world. One of the main driven of global warming is from human activities. We have to cooperate together, help each other to reduce global warming before it too late. And I also have some questions. As you can see in the map that at the edge of Greenland is green, I want to know why it’s not cover of ice? And is it true that Greenland now is greener than in the past?

Onpimon at 01:35 AM on 30 March 2018

Antarctica is too cold to lose ice

I agree with this article.I also had read an article from Boston globe, it’s an article about severe melting of ice sheet that is found in Antarctica. It’s said that a team of European scientists has found some ice sheet melting in East Antarctica during the summer months, in an area that is supposed to be too cold for perceptible ice loss. The ice sheets is weak throughout its structure. The glaciers is a large mass of ice, so it’s very hard to melt or it will take a long time to melt. But now it not take long time as in the past to melt. The glaciers are melting because of warming ocean water. Warming ocean water is caused by global warming. We have to solve this problem straightforward. In this article it’s said, we should all now at least remotely understand that mass balance changes in Antarctica aren’t reliant on surface melting but rather depend on dynamic responses such as the 2ndmechanism. I also have a question. Is it possible for melted ice to form its original ice form again?

jef12506 at 00:13 AM on 30 March 2018

How could global warming accelerate if CO2 is 'logarithmic'?

Very carefully considered post but you left out as much or more than you include.

There are dozens of feedback mechanisms that are kicking in and really need to be included in the warming graphs. What about water vapor for one, the biggest one at that? Just plotting CO2 and announcing future warming is less than useless it is dishonest.

Also there is plenty of documented cases of natural sinks absorbing less and even starting to become emission sources such as forests.

The over all message of this post is that it is bad but not that bad and we have time so don't worr too much. I understand not wanting to upset people too much or cause panic but I believe that mentality is more harmful that good.

We need to state how bad it really is and that chanses are it is happening faster than expected using the same clear, considered, scientific evidence and let the public have the knowledge they need to make the right decisions.

Science does not get to decide how much truth we get to have.

citizenschallenge at 23:33 PM on 29 March 2018

How could global warming accelerate if CO2 is 'logarithmic'?

DPiepgrass nicely written article. I'm looking forward to your future posts.

Eclectic at 19:36 PM on 29 March 2018

Great Barrier Reef is in good shape

Ping34 @ post #2 , you are correct. The Great Barrier Reef has suffered much damage from (mostly) the increasing water temperatures. And it will get worse, because global warming is continuing, and the politicians of the world are making only minor effort to counter the effects of CO2 emission.

The GBR is large — about the size of Italy — and not all of its beauty has been destroyed (so far). The local tourist industry does not like to mention the damage, or that the damage will almost certainly increase over the next decades. And Australians do not like to think about the situation. Also, other coral reefs in other places, are being damaged. But the GBR is the most important and beautiful of them. Ping34, if you wish to see the GBR, you should visit it as soon as you can. Do not wait for 10 or 20 years.

There is one hope. Scientists are studying ways of selective breeding of corals which are more resistant to high temperatures. It is uncertain how much success they will have; or how well they can re-populate such a large reef in just a few decades; or if they can re-create the numerous varieties of corals which give the reef its beauty and provide the habitat for the many beautiful varieties of fish.

Tminus at 18:22 PM on 29 March 2018

How could global warming accelerate if CO2 is 'logarithmic'?

Thank you for your article. Your mention of Methane in your second point might need revising: "...but what's really important here is that it has a short lifetime of only about 12 years before it is destroyed in the methane cycle. That makes the methane problem much less serious, as we expect nature will clean up the mess when we eventually reduce our methane output."

At least one study I've read about recently shows we've greatly underestimated methane's role. In the PNAS paper "Centuries of thermal sea-level rise due to anthropogenic emissions of short-lived greenhouse gases" (http://www.pnas.org/content/114/4/657), its authors state, "We show that short-lived greenhouse gases [e.g., methane] contribute to sea-level rise through thermal expansion (TSLR) over much longer time scales than their atmospheric lifetimes."

And "...at least half of the TSLR due to increases in methane is expected to remain present for more than 200 y[ears], even if anthropogenic emissions cease altogether, despite the 10-y[ear] atmospheric lifetime of this gas."

Eclectic at 17:27 PM on 29 March 2018

No warming in 16 years

Pacharaporn K @ post 15 , the article indicates that our planet continued to warm during the "16 years" (16 years up to May 2013).

Please note that the article is now nearly 5 years old. The SkepticalScience website is managed by a small group of volunteers (and is not supported by money from governments or even the Oil Industry). So the large numbers of articles here are often not kept up-to-date. However, you will keep up-to-date about climate news, if you frequently view the Home Page, where new articles and news links are mentioned daily or weekly.

The evidence for the continued warming of our planet (even during the "16 years") is :-

(A) measurements show that the ocean continues to warm, as shown by the continued increase in OHC [Ocean Heat Content],

(B) the continued presence of excessive CO2 gas in the atmosphere, is showing that there is no reduction in the Greenhouse Effect (and so there cannot be a real pause in short-term and long-term warming),

(D) the continued rising of sea-level (from melted land ice, and from thermal expansion of sea water),

(E) the important "surface temperature" (where we humans and animals and plants are living) shows continued warming during every 30-year period [climate changes are measured over a 30-year minimum period]. Therefore any short-term period (such as 8 or 16 years) with a pause or decline in surface temperature . . . is not important and does not show any significance — unless a real cause is found for reduced warming (for example: a very large volcano eruption, or a sudden very large rise in industrial aerosols which reflect sunlight).

You will notice that after 2013 came the much hotter years 2014, 2015, 2016, and 2017 . . . where global land and ocean surface temperatures were very evident (as measured by the American NASA and NOAA [U.S. National Oceanic and Atmospheric Administration] and by the Japan Meteorological Agency and by many other national agencies around the world).

The planetary surface temperature has reduced very slowly over the last 5,000 years. But it has not reduced as fast as expected, because humans have caused a small amount of warming force by clearing forests for cereals agriculture and also by (methane gas production from) rice paddies. And now for the past 100 - 200 years, the burning of coal and petroleum oil has produced a strong and rapid reversal of the long-term natural cooling cycle. Big changes are coming — and most of them will be bad for the world and human societies.

Pacharaporn K. at 17:22 PM on 29 March 2018

It's not happening

I like that you devide and explain each indicator clearly. Every evidences are really make sense follow your claim, but I just wondering how can it happen because the weather is become really hot nowadays and seems going to be hotter and hotter? Also ice ages are become smaller than what it was. How can the result be the opposite with the indicators? Is it because of there areb still many factors going on?

Thank you XD

Ping34 at 17:20 PM on 29 March 2018

Great Barrier Reef is in good shape

In the article, it mentioned that CO2 dissolves in water and causes ocean acidification. Therefore, the CO2 amount are highly found in both atmosphere and ocean? If so, then GBR is really in big trouble because this is a big synergy caused from both the global warming and ocean acidification. Am I understand correctly?

One Planet Only Forever at 05:25 AM on 29 March 2018

Study: wind and solar can power most of the United States

shastatodd@2,

An understanding that is related to my previous comment is: If the 1% of the total current population (about 75 million people) that 'per-capita causes or personally benefits (profits) from the highest levels of consumption, waste and negative impacts' became Zero contributors to the problem there would be a far greater than 1% reduction of the problem.

And the actions of those 75 million would provide education and leadership toward ways of living that the other 99% could sustainably develop to also enjoy.

The only potential problem is that those 1% would no longer be able to appear to be, or put on a show of appearing to be, the Biggest Winners. However, any perceptions that are not the result of living/acting in ways that are truly sustainable and helpful to others will only be temporary delusions of grandeur and superiority.

gws at 03:55 AM on 29 March 2018

In court, Big Oil rejected climate denial

I find it remarkable to argue that

"... climate change is caused 'largely by economic and population growth' ",

since that is only the case because of fossil fuel use. Both economic or population growth can of course occur as a result of energy availability (as a proxy) from other sources. And that qualifies the quote/argument above squarely as a non-sequitor fallacy.

Thanks for the links JH !

One Planet Only Forever at 02:08 AM on 29 March 2018

Study: wind and solar can power most of the United States

shastatodd@2,

I agree that high levels of consumption and waste are a serious concern.

My recommended solution is to demand/require the wealthiest and most powerful to lead the develpment of 'low consumption, no-negative-impact, zero-waste' ways of living that the entire population can develop to enjoy virtually eternally on this, or any other, amazing planet.

The Winners are the ones who can afford to behave better. And they are the ones who should not be allowed to claim that 'they did not know better'.

It boils down to correcting the incorrectly developed socio-economic-political systems to restrict the freedoms of people to 'believe what they want and do as they please', with more restrictions as people become wealthier and more influential. The wealthiest and most influential should only be allowed to properly increase the awareness and understanding of the entire population about how to develop sustainable ways of living.

Allowing Winners to do as they please, the standard Libertarian argument, is undeniably a recipe for disaster. It has been proven to develop self-reinforcing systems that are certain to result in the development of more damaging irresponsible undeserving Winners, unless those type of winners get caught/penalized/restricted.

Pacharaporn K. at 02:08 AM on 29 March 2018

Climate scientists are in it for the money

Wow, thank you for posting this wonderful article. For me, scientists are playing really important roles. Without them, how can we know what is going on in this world. Especially about climate change which we should concern the most. If be a scientist is that easy and rich, it is going to have a billion of scientists out there! It is a really hard job. I appreciate all of them a lot. Thank you for hard working! Anyway, I still have a question;

Do scientist need to belong to a company?

Pacharaporn K. at 00:51 AM on 29 March 2018

No warming in 16 years

The article claims that the temperature of this blue planet has not increased for the past 16 years. Also they came up with some evidences to shows what has influenced the recent temperature trend like less solar energy and the El Niño oscillation. All evidence looks to flow in the same direction......good claims and perfect evidence, but it is opposite with what I have learned to be so far. I thought human activities should be the primary causes that have led this world to what we are experincing nowadays?

(p.s. I'm just a high school student so, sorry for my doubt XD)

Thank you for your respond!

John Hartz at 00:02 AM on 29 March 2018

In court, Big Oil rejected climate denial

Recommended supplemental reading:

Climate Denial Arguments Make Their Way to Federal Judge’s Science Tutorial by Amy Westervelt, Climate Liability News, Mar 20, 2018

8 Answers to the Judge’s Climate Change Questions in Cities vs. Fossil Fuels Case by John H Cushman Jr, InsideClimate News, Mar 20, 2018

In Climate Tutorial, Oil Industry Doubles Down on Science Uncertainty by Amy Westervelt, Climate Liability News, Mar 22, 2018

dfish at 22:55 PM on 28 March 2018

Students from KMIDS college in Bangkok posting comments

This is a fantastic idea! I really like that part of the assessment is the value-add of the students comments. Keep up the good work!

DPiepgrass at 18:49 PM on 28 March 2018

CO2 limits will hurt the poor

I skimmed Samson et al 2011 and found it bizzarely obsessed with population density. Perhaps I am not understanding the paper, but it seems to be saying "high population density is good, rural living is bad, and climate change is projected to increase conditions correlated with rural living, especially in poor countries, so that's bad." Surely this is an overly narrow and simplistic perspective. Have I misunderstood? In the "Notes" below these comments there are more sources; Patt et al. (2010)'s focus on extreme weather made more sense.

I learned the most by reading the IPCC report (AR5 WG2 Chapter 11 pages 721-732):

Most of the poor people in the world live near the equator where the weather is hot. Global warming means higher average temperature, and worse heat waves. Heat waves kill many people every year. High body temperature can decrease physical abilities and mental function, and is uncomfortable. Example: in Australia, the number of “dangerously hot” days (when core body temperatures may increase by ≥2°C and outdoor activity is hazardous) is projected to rise from 4-6 days per year to 33-45 days per year by 2070.
During extreme heat, danger to health is higher for manual laborers, including farmers. Poor people usually do not have enough money for air conditioning.
Climate change is a threat to crop productivity in areas that are already food-insecure. Climate change will reduce food availability, and will cause undernutrition in children.
Floods are the most common natural disaster. It is expected that more people will be exposed to floods in Asia, Africa, and Central and South America. Increases in intense tropical cyclones are likely in the late 21st century.
Climate change is likely to increase the risk of malaria, and perhaps Dengue fever.
Higher temperatures are associated with more diarrhea. Bacterial pathogens are more likely to grow on produce crops (e.g., lettuce) in simulations of warmer conditions. This hurts poor people, who have less access to health care, more.
Human conflict is increased by soil degradation, freshwater scarcity, and other forces related to climate. So climate change can make armed conflicts worse.

Also, fossil fuels cause air pollution. Usually, poor countries have lower standards against pollution, so poor people breathe much more air pollution for each unit of "unclean" energy produced nearby.

Ari Jokimäki at 16:38 PM on 28 March 2018

They changed the name from 'global warming' to 'climate change'

I also agree with emmy.

Glenn, "Climatic change" has been used before Plass in the same meaning. An example is Manley (1944) discussing Callendar's work. Callendar himself also has used the term, at least in his 1949 paper. I studied the history of the terms in scientific literature some time ago, and earliest use of "global warming" I found was in 1961. "Climate change" was used as early as 1927, if I remember correctly (but that was not used in the modern sense), and "climatic change" could be traced back to 1850s at least.

Another, even broader term that is relevant here is "global change", which is commonly used to describe the overall environmental change happening on Earth (in addition to climate change, it describes the change in the biosphere for example).

Also on terminology, the greenhouse effect used to be called "selective absorption of the atmosphere" in 19th century.

Glenn Tamblyn at 16:14 PM on 28 March 2018

They changed the name from 'global warming' to 'climate change'

emmy

What you said is correct. There is also a 3rd term that only gets used occassionally. The Enhanced Greenhouse Effect. We can think of it like this.

Adding CO2 and other greenhouse gases increases the strength of the greenhouse effect, 'enhances' it.
This then causes more heat to accumulate and, on average the Earth warms up - Global Warming.
Then this warming has other effects, increased evaporation from the oceans, so more rain, shifts in weather patterns and local climates, etc. Also chemical changes in the oceans - Climate change.

The first use I am awars of of the term Climate Change was in a paper by Gilbert Plass in 1956 titled 'The Carbon Dioxide Theory of Climatic Changes' - note he used Climatic, not Climate. And the Climate Change Plass and people before him were more interested in was the answer to what caused the ice ages. It was only as they investigated this question that they started to realise that this might mean climate changes in the future as well.

Glenn Tamblyn at 15:58 PM on 28 March 2018

We didn't have global warming during the Industrial Revolution

warrissaru.su

There are several factors that have influenced CO2 levels since the industrial revolution, not just CO2 from burning fossil fuels, although that is he biggest factor. Also likely other factors before the industrial revolution

CO2 from fossil fuels is the biggest factor
CO2 from land clearance is an important factor. Clearing forest particularly to make agricultural land means the carbon from the forests ends up in the atmosphere. Often this change means more carbon is released from the soil as well and this can be bigger source than the original forest. Land clearance has been a common means of producing food for 1000's of years. Not only to make more farmland, but because land that has been cleared may only be fertile for a few years then more land has to be cleared. Only some soils and climates are suitable for being continuously farmed for very long periods without artificial fertilisers which only were important from the mid-20th century onwards. Paddy based rice farming in Asia combined with things like the use of 'night-soil' in Japan are examples where land can be used for long periods.
As farming increased, release of more methane occurred due to changes in land use and the presence of many more animals. Methane is a powerful greenhouse gas, then eventually becomes CO2 in the atmosphere.
from the mid 20th century on, the use of nitrogen based artificial fetilisers increased the crop yields of much farmland. But this also increased emissions of Nitrous Oxide, a greenhouse gas.
Later the development of refrigerant gases for refrigeration such as CFC's and later HFC's meant they also started to be added to the atmosphere and are greenhouse gases.
There is reasonable evidence that humans have had a smaller but still real effect on the climate for 1000's of years. The early development of farming and land clearing, domestication of animals, and particularly the development of the wet paddy system of rice farming 1000's of years ago appears to have meant the Earth didn't cool down as much as we would expect over those years. Professor Bill Ruddiman and his team have investigated this for many years.
He even thinks that major social events in the 15th to 17th centuries may have had small climate impacts. A substantial culture in North America, based in the Mississippi Valley collapsed shortly before Europeans arrived in America. This society had substantial towns and small cities, agriculture etc. Then after it had collapsed, the arrival of Europeans introduced diseases that devastated the native American population. Most of this impact was unintentional by the Europeans although there were some bad cases of deliberate infection. The population of native americans crashed. And a reforestation of farmland may have happened as a result, reducing CO2 levels slightly. A second effect later may have occurred due to the slave trade. The population of West Africa may have dropped significantly due to the slave trade to the Americas and reforestation of farmland in west Africa may also have lowered CO2 levels a little.

Glenn Tamblyn at 12:55 PM on 28 March 2018

Scientists can't even predict weather

Kotchakorn

The scientists aren't trying to predict the weather in the future, they are trying to predict the cimate. What is the difference? Climate is the average of the weather, normally considered as the 30 year average. Weather is what happens day-to-day. Predicting the two is quite different. Let me use two examples to highlight this.

1. A man is walking his dog along the beach. The dog is on a lead. If we watch the dog it wanders up and down randomly, down to the waters edge, up to sniff some seaweed - quite random. But the man is walking in a straight line along the beach, and the dog's movement is limited by how long the lead is. Can we predict exactly where the dog will be when the man has walked further along the beach? No, that is like predicting the weather. But we can predict that if the man continues along his current course, the dog's position will be within a certain distance from the man.

The dog is weather, random, but a bounded randomness. The man and the length of the lead is climate. If the man continues on the same path, with the same lead, the climate hasn't changed. If the man moves higher up the beach, the dog has to go with him. The dog can now reach higher up the beach, but it can't reach as close to the water. When the man moves, the climate has changed.

2. Or consider a swimming pool. It has a certain amount of water in it. If nobody uses the pool for a long time its surface will be very smooth and level. It is easy to estimate how much water is in the pool.

But if people are using the pool the surface is very rough and unven. Each little wave and trough is like the weather, random. But if the amount of water in the pool doesn't change, then the waves are all within a certain height of each other. The waves on the top are the weather, how much water is inthe pool is climate. Predicting one if very different from predicting the other. And if we add more water to the pool, that is like changing the climate.

nigelj at 10:45 AM on 28 March 2018

In court, Big Oil rejected climate denial

Big oil funded the Heartland Institute, when they could have chosen to fund other business lobby groups less in denial about the science. Its got guilt written all over it.

bjchip at 10:10 AM on 28 March 2018

In court, Big Oil rejected climate denial

Thus setting themselves up nicely for an argument

"Look, we don't control these guys"

even as the indirect funding continues.

Also that Exxon != Chevron.

DPiepgrass at 09:58 AM on 28 March 2018

It's methane

In recent years, atmospheric methane concentration has increased again. It has been reported that "if you leak more than 2 or 3 percent [of methane] it’s worse for climate change than coal", so I checked Google Scholar to find out whether U.S. fracking might be why methane increased. In short, the answer is no. Nisbet et al. (2016) says

"since 2007, growth has resumed, with especially strong growth in 2014. Evidence from carbon isotopes implies that the primary cause of the new growth is an increase in biogenic emissions, probably from wetlands and also agricultural sources, such as rice fields and cattle. The evidence presented in this research study, from a wide range of measurement sites both in the northern and southern hemispheres, suggests increased tropical emissions, for example from tropical wetlands, may be a principal cause of the global rise in methane. Contributions to the growth may also come from agricultural sources and perhaps some fossil fuel emissions also."

But people should realise that CO₂ builds up in the atmosphere, so natural gas still causes global warming even though it emits less CO₂ than coal.

nigelj at 07:13 AM on 28 March 2018

In court, Big Oil rejected climate denial

Good article on the legal background: Two Major Climate Change Lawsuits Move Forward

nigelj at 06:18 AM on 28 March 2018

Study: wind and solar can power most of the United States

shastatodd @2

"please, this is hopium bullshit. there is no way 7.6 billion rapacious human animals (increasing at 1,000,000 ever 4.5 days) can live our lifestyles of waste and massive consumption on "magic green", which by the way is 100% dependent on the underlying, fossil fuel powered industrial infrastructure. please familiarize yourself with the limits to growth. technological cornucopianism cannot mitigate finite planet realities."

Why not? Lets take some specific examples. Theres enough lithium in known current reserves for one billion electric cars. Lithium reserves data here.

Lithium can be recycled endlessly, so thats enough for hundreds to thousands of years of use provided waste is minimised. This is before we get to new discoveries of lithium, more efficient use of lithium, aluminium based batteries, and the new carbon based batteries.
The same principles tend to apply to other materials.

Yes minerals are a finite resource, but they can be recycled where fossil fuels cant be recycled. Provided we use mineral resources wisely we can maximise technology. I do believe however that we are going to have to be more prudent in how we use resources, with some reduction is use, and prioritising of essentials and population growth must stop. But that is not incompatible with renewable energy at a decent level.

nigelj at 06:02 AM on 28 March 2018

Study: wind and solar can power most of the United States

jef @1

"There is no question that solar and wind can provide our energy. The real question is how much energy, can we use it easily, and can how much does it cost. We can't afford the cost of slightly more expensive FF energy, there is not enough surplus to drive the economy so how can we afford more expensive, less surplus solar and wind?"

The article answered how much energy. Solar and wind can provide up to 80 - 90% depending on the two scenarios. I mean with respect I don't understand how you missed that, unless you were concerned about future demand or something? There's no reason to belive this would be a problem.

It's hard for me to see why the energy would be hard to use. It's the same electricity as any electricity, and is transmitted the same way. Some lines upgrades would be required of course because of inter state transmission to deal with intermittency issues, although this depends on which option is preferred. The article demonstrated that intermittency issues can be dealt with effectively in varrious ways.

I don't understand how you can claim we can't afford the cost of "slightly more expensive" energy. If its only slightly more expensive, then by definition it's affordable. Buy slightly fewer coffees or something. Poor people are the one group that might struggle, but they could be subsidised.

Wind power and solar power is now very affordable low cost power in general terms. Its the same cost as coal in some places, and is expected to be cheaper in the future. Lazard cost analysis here. Prices had literally plumetted in recent years.

"When ever an author puts "Imagine..." in an article it should be dismissed. If we had the storage tech we could cut FF use for electricity by more than half right now. What makes anyone think we will do it later if we can't do it now?

Maybe the article worded it less than ideally, but battery storage is improving fast and its not unreasonable to conclude costs will drop in the future very significantly. Likewise there can be good confidence wind and solar prices will continue to drop. Solar may be nearing the limits, but wind could drop considerably further yet.

The article suggested one scenario of 80% renewables and 20% hydro nuclear etc. This is a very affordable option right now, and a total system would not be hugely more expensive than coal. Given price trajectories its very likely such a system could be cheaper than coal in the near future, and the nuclear component might not be essential and it may be viable to use battery storage or hydro storage. Such decisions do not need to be finalised until the renewable component of the grid starts to get over about 30%. Alternatively, theres the other option that uses a surplus of wind and solar power, and less use of hydro and nuclear etc.

Of course we would have to replace existing coal fired power for example, sometimes before it's at the end of its life. Costs of completely converting a totally fossil fuel grid including generation and transmission lines upgrades have been estimated at 1% of a countries total gdp (gross domestic product) per year, and quite probably less, a number that is clearly not "unaffordable". In return we get clean energy, a more sustainabe form of energy, and a system that is very likely ultimately cheaper tnan fossil fuels, so whats not to like?

ubrew12 at 05:38 AM on 28 March 2018

Study: wind and solar can power most of the United States

In a world of self-driving cars, floating offshore windpower should really not be all that difficult. Put each tower on GPS and let it stationkeep with onboard navigation and power from a combination of wind and wave (no wind and wave= no need to stationkeep). Each tower should be floating, perforated to allow wave action to go through and around it, and anchored 100ft below the surface to plastic sheeting (i.e. a 'water-brake'). At 100 ft and below, surface wave-action is negligible. A water-brake of sufficient size and perhaps multiple levels can be designed to hold the tower quite still, even in the waves of the N Atlantic). You can design the tower so that, absent the force of its own buoyancy, it tends to sink from wave action more than rise, so that it tends to align itself with the wave-troughs rather than the wave-crests. Thus the water-brake is in no danger of being pulled to the surface and destroyed by waves. After securing a stable platform via sunken water-brake, but still an untethered platform capable of being motored horizontally using locally available power and GPS, then its just a matter of making the tower tall enough to clear the tallest waves. This kind of windpower favors very large blades the size of jumbo jets. Since the system is unanchored, probably one of the most expensive parts of this system is the (sunken) power feed back to land. The advantage of floating offshore wind power is it has little to no NIMBY effect and the wind is stronger. I sent a design concept to GE a few years ago but they passed.

One Planet Only Forever at 02:16 AM on 28 March 2018

CO2 is not a pollutant

Aomsin@34,

You provided two definitions of pollution then provided the connection between human created CO2 from burning ancient buried hydrocarbons to the second definition.

Think seriously about why you opened your comment by declaring "I think carbon dioxide is not a pollution."

The interpretation of the definition is a game played by legal-minded people trying to argue against government regulations to limit harmful impacts of human activity. The EPA written legal mandate is to limit 'pollution'. That is the cause of the attempts to legally argue that CO2 from burning fossil fuels is not 'pollution' (an argument has been lost in the courts). Continuing to argue about the definition distracts from the undeniable harmful consequences of the activity. And regulatory bodies like the EPA should act to restrict the creation of harmful consequences, no matter what term is used to describe them.

shastatodd at 00:47 AM on 28 March 2018

Study: wind and solar can power most of the United States

please, this is hopium bullshit. there is no way 7.6 billion rapacious human animals (increasing at 1,000,000 ever 4.5 days) can live our lifestyles of waste and massive consumption on "magic green", which by the way is 100% dependent on the underlying, fossil fuel powered industrial infrastructure.

please familiarize yourself with the limits to growth. technological cornucopianism cannot mitigate finite planet realities.

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