A flow chart showing the interrelated concepts around human activity, global warming, and climate change.
A flow chart showing the interrelated concepts around human activity, global warming, and climate change.
Global warming, climate change, and the climate emergency.

If the Climate Change Crisis were World War II, it’s 1939

but everyone is acting as if it’s the Roaring Twenties

Dave Sag
Dave Sag
Aug 24, 2019 · 16 min read

A standard trope of the climate change denier is that “they”, some unnamed shadowy cabal, stopped referring to “global warming”, and instead rebranded it as “climate change”. While there is some evidence to suggest that this rebadging was attempted by elements of the fossil fuel lobby, the fact is that global warming is not the same thing as climate change; global warming is a driver of climate change.

Climate Change 101

It’s been understood for over a hundred years now that Earth’s atmosphere traps heat by what’s known as “The Greenhouse Effect”. While the physics are not exactly the same as in an actual greenhouse —Earth is not shrouded in a layer of glass after all— the analogy is sound. Certain atmospheric gases, primarily carbon dioxide, but also methane, various nitrogen molecules, and others, trap heat. If you add more greenhouse gases, you trap more heat.

By burning fossil fuels, we release energy that took many millions of years to store, and with that energy we release a lot of greenhouse gases. For every tonne of carbon we burn we release approximately three and a half tonnes of CO₂. Why? By burning the carbon we cause it to combine with oxygen. CO₂ is literally one atom of carbon combined with two atoms of oxygen. And oxygen is a bigger, and heavier atom than carbon. There are many other greenhouse gases, such as methane, and while we don’t emit anywhere near as much methane as we do CO₂, methane hangs around in the air much longer, and is more effective at trapping heat. Methane is around 20 to 30 times more potent a greenhouse gas than CO₂ is, so it’s a really good thing we don’t emit as much of it. Nitrous oxide is around 250 to 300 times more potent a greenhouse gas than CO₂. This potency is called a gas’s “global warming potential”, and it’s baselined against CO₂ because CO₂ is the most common greenhouse gas emitted by human activity, and it’s ultimately the biggest contributor to global warming.

Human activities such as power generation, deforestation and land-use change, transport, shipping, and so forth, all cause the equivalent of over 40 billion additional tonnes of CO₂ (equivalent) to enter the atmosphere every year. We’ve been doing this at a mostly increasing pace since around 1760, the beginning of the industrial era. Pre-industrial Earth’s atmosphere contained around 280 parts per million of CO₂, and now it’s around 415 parts per million. That’s not a huge amount in terms of the overall mix of atmospheric gases, but it’s a huge increase, and it’s having a measurable effect on the global mean temperature.

I’m not going to get into all the typical denialist arguments about how volcanoes also emit greenhouse gases, and how water vapour is also a greenhouse gas, and how it’s not really happening at all, and it’s the sun, and so on and so forth. Those arguments are bunkum and have been widely and convincingly discredited already. The basic facts are that human activity causes more greenhouse gas to be emitted, more greenhouse gases trap more heat, and heating up a closed system like the Earth causes all sorts of changes to established climate patterns. These changes to the climate are what we call “climate change.”

Human activity -> greenhouse gases -> global warming -> climate change

Other Pollutants

Human activity does more than just emit greenhouse gases. We emit all manner of other pollution as well. I’ve been living in India for the last couple of years, and have been exposed to some of the horrors of this first-hand. In Delhi, the air in winter is so toxic you would be crazy to choose to go out into it. In Bangalore, there are rivers which spontaneously catch fire due to the high levels of toxic waste in them. You can’t travel anywhere in India, or in many other parts of the world, without seeing rivers and waterways choked with plastic bags, chip packets, old cigarette cartons, and more. There are such high levels of antibiotics in Indian waterways, and therefore food, that just living there for a year is enough for you to be almost guaranteed to be colonised by antibiotic resistant bacteria.

Human activity is choking the oceans with plastic, killing sea life globally. Combined with rampant over-fishing, it’s estimated that we are well on track to kill most living things in the planet’s oceans within the next 50 to 100 years. A lot of the CO₂ we emit into the air gets absorbed by the oceans, reacting with water to form carbonic acid. We’ve measurably changed the pH level of the oceans, making them more acidic, as well as warmer. As the waters get warmer and more acidic, many fish species simply can’t survive, or can’t breed. Shellfish can’t form their shells. Seafood amounts to around 40% of global food stocks, so when we lose that, as is now completely inevitable, we lose 40% of the very basis of our food supply.

Jellyfish however love warmer, more acidic oceans, and vast swarms of them have been known to swim up the outlet tubes of seaside nuclear reactors, choking them completely, and forcing them to be shut down. None of the climate models predicted this kind of behaviour.

We also burn and cut down forests at a massive scale, reducing the planet’s ability to photosynthesise CO₂ back into O₂, and emitting huge amounts of CO₂ simply from the industrial activity that comes from logging timber and converting rainforests to cattle grazing land. Deforestation is the single biggest driver of greenhouse gas emissions and, at current rates, it is unlikely to stop until the very last tree is cut down.

Human activity -> greenhouse gases -> global warming -> climate change
-> ocean acidification -> food shortages
-> other pollutants -> water shortages
-> animal die off -> food shortages

Why is Global Warming a Problem?

If you take a relatively stable closed system and add more heat to it, you increase the overall energy level of the system. While energy levels are increasing, the formerly stable system becomes unstable. You can see this simply by boiling a pan of water. As the water heats up, it moves, until it reaches a point where it can’t absorb any more energy, and then the whole system breaks. The water all becomes steam, the steam super-heats, and eventually you exceed the melting point of the pan itself.

In the case of the Earth, while there has always been natural climate variation, and long-term climate cycles driven by our varying proximity to the sun, flux in solar energy output, and gradual changes in the planet’s atmospheric mix, the fact is that, for the last few hundred thousand years, the planet’s climate has been incredibly stable, and this has allowed life as we know it to flourish.

But as we’ve started noticibly warming the planet, we are noticing some very specific climactic changes. When I was younger, there was never such a thing as a “polar vortex,” (well there was, but I’d never heard of it) that mass of freezing weather that hits Northern Europe and North America now on an almost annual basis. It’s paradoxical that global warming would cause this freeze. The reason it’s become more common is because the Jet Stream, a current of warm air that moves from the southern to the northern hemisphere, has weakened, and that’s made the polar vortex more likely to dip south.

Similarly, but under the ocean, The Gulf Stream is slowing. Melting ice from Greenland and the Arctic circle is diluting the salinity of the water in the Gulf Stream, a massive Atlantic current that transfers a vast amount of heat from the southern hemisphere to the northern hemisphere. This is causing the Gulf Stream to move more slowly, and it’s actually changed course slightly, so that now all the warm water that used to reach the North Sea, now peters out somewhere south of the UK. So there’s big empty parts of the Atlantic getting that heat and there’s huge, populated parts of the world that are now missing out.

Global warming is also changing the shape of the waves that in turn shape coastlines around the world, with a warmer world affecting around half of all the world’s coastlines. Changes to the height, direction, and frequency of waves will have unprecedented effects, on top of the havoc that rising sea levels will wreak.

Australia, currently the world’s third biggest fossil fuel exporter, has always struggled with drought, especially in the south, and it’s also always suffered from flooding in the north. Droughts come and go with the regular La Niña and El Niño climate cycles that ebb and flow across the southern hemisphere. But a warmer planet has disrupted those regular cycles, exacerbating Australian drought and flooding. More drought means animal and plant die-off, higher risk of wild fires (or as we Australians call them, “bushfires”), and a whole range of economic impacts. Hotter, drier conditions also encourage people to run air conditioners more, consuming more energy, emitting more greenhouse gases, and warming the planet even more in a vicious circle. This is one, albeit quite minor, feedback loop that is causing global warming to accelerate.

Global warming is melting ice caps at a much faster rate than any of the optimistic models suggested. In fact it’s tracking with pretty much all of the worst-case scenarios that were outlined around 30 years ago when scientists really started getting worried that something was going wrong with the planet’s climate, and started looking at why. It was accepted very quickly that the why was human activity, but a whole industry of denial emerged to cloud that view.

Melting ice caps, as well as the melting of other long-term ice structures such as glaciers, causes both the gushing of fresh water into the oceans, playing havoc with fish and sea life that evolved in saline environments, changing major ocean currents such as the Gulf Stream, and causing instability in mountainous regions such as the Himalayas where glacial run off that is the source of up to a quarter of the world’s fresh water is now drying up, or coming in uncontrolled bursts, known as glacial lake outburst floods (GLOFs), causing regional flood events, mud-slides, and avalanches. This is putting pressure on water and food supplies across vast swathes of the planet, and leading to accelerated animal and plant habitat loss and die-off.

The loss of all this ice also has another profound effect: that of reduced albedo. Albedo is the term used to describe the reflection of heat from the planet. Ice is white, and white surfaces reflect heat. Reduce the ice coverage, and you reduce the amount of reflected heat. So much ice has been lost already that this reduction in reflected heat has measurably contributed to the acceleration of the warming of the planet. This in turn drives more ice loss, and so is a vicious circle that will only stop when there is no more ice.

Another issue with ice sheet loss is that when you move several billion tonnes of ice from land to the sea, not only do the sea levels rise, but you also change the loading on the tectonic plates that form the Earth’s livable surface. The world we know is actually a set of massive plates, between 15 and 200 kilometers thick, that slowly drift about on the surface of a molten core. Mountain ranges such as the Himalays are caused by two of these plates slowly but inexorably smashing into each other at a rate of around one centimetre per year. Other parts of the world are slowly being pulled apart. The whole world is in a very slow state of flux.

Shifting billions of tonnes of ice around very quickly is like rolling a golf ball around on a plate that’s resting on a waterbed. You get ripples, and on Earth those ripples can manifest as volcanic eruptions and earthquakes. Indeed when geologists look at the changes on Earth over the few hundred thousand years that ice ages took to either set in or thaw, there is evidence to suggest that those changes were accompanied by a significant increase in seismic and volcanic activity. Volcanic eruptions spew greenhouse gases into the air. Not anywhere near as much as human activity does, but not an insignificant amount either. And it goes without saying that more earthquakes mean all sorts of trouble, from tsunamis to the destruction of a whole range of habitats and infrastruture.

Melting ice caps increase sea levels, making coastal areas uninhabitable, causing whole islands, and soon whole countries, to sink into the ocean. If a single multi-billion tonne chunk of Greenland ice were to suddenly slide off into the ocean, the resulting tidal waves could wash right over the UK to a depth of around 600 metres, and cause serious flooding right into the middle of Europe, Canada and the USA. Ripples would be felt around the world and the overall sea level would jump about a metre. That translates to billions of square kilometres of populated coastline lost to the ocean.

Even without such dramatic collapses, climate change is already starting to drive mass migration as human populations grow while water and food runs out, and livable regions become unlivable. Migration, as we have seen over the last few decades, is a highly contentious issue. Up to a billion people on the move is going to cause global conflict, the likes of which my generation has never seen.

Feedback Loops and Runaway Global Warming

As previously discussed, a classic feedback loop is that we melt more ice, reflect less heat, make the planet hotter, which melts more ice.

There are vast deposits of methane trapped in the ocean in a form known as clathrates. These are giant columns of methane that are held in place because the water they are in is very cold. As the oceans get warmer, and as the ocean chemistry changes, those clathrates can become unstable and occasionally they collapse, releasing all that methane into the air.

Similarly there are vast deposits of methane trapped underneath permafrost in the nothern hemisphere. When they pop you can get massive and sudden sink-holes, and huge plumes of methane which suffocate everything in the vicinity. That’s bad, but the worst consequence is that all that methane enters the atmosphere, causing sudden spikes in global greenhouse gas levels. This will accelerate global warming and ocean acidification. Like ice-sheet loss, this is a vicious circle that will only end when all of the clathrates and other trapped methane deposits are vented into the atmosphere.

The danger is that these feedback loops will trigger what’s known as runaway global warming. The effect of that is that the global planetary temperature rises so much that the Earth becomes not just incompatible with human civilisation (that’s already pretty much a given outcome of even the most optimistic scenarios now) but it becomes incompatible with life itself. The oceans become so acidic that not even jellyfish can live in it, the air becomes unbreathable, and the temperature of the planet becomes hot enough to boil off the atmosphere to the extent that solar radiation scorches the whole planet, finishing the job. That kind of doomsday scenario is not just possible, it’s a likely outcome.

What Do People Mean by “Climate Emergency” or “Climate Crisis”?

The Paris Agreement is intended to restrain global warming to 1.5°C above pre-industrial levels, with the IPCC advising that doing so is still possible and will reduce the risk of runaway global warming to a mere 50%. Let’s be clear; 50% is still a massive chance of failure, especially when talking about existential risks.

Recently the terms “climate emergency” and “climate crisis” have started to be heard. Governments have started to “declare a climate emergency”. The deniers have jumped on this saying “they used to call it global warming, then climate change, and now it’s a climate crisis”, as if there was actually no cause for alarm.

The “climate crisis” is a political response to the predicted effects of climate change. Climate change, to reiterate, describes the changes to the global climate caused by global warming, which is the warming of the planet due to human activity.

“It’s a statement from the Parliament that the situation is so urgent it requires the whole country to pay attention and take action” — Adam Bandt

When you get mass die-offs of animals, plants, and the collapse of entire human societies, the appropriate response is that of a crisis or emergency. When mass conflict breaks out due to population pressure, migration, food and water shortages, and loss of livable land, the appropriate response is that of an emergency or crisis. When things have reached a point that a business-as-usual response is not likely to have any effect, then an emergency or crisis response is warranted.

“When governments declare emergencies for things like war or drought, it’s a message to the whole country that the situation is serious, and we all need to mobilise to address the threat. It’s like getting Parliament to call triple 0 [like 911 for American readers], to get the government to start acting and put out the huge fire that is global warming,” explains Australian Greens MP Adam Bandt in a recent interview.

It’s unclear however what sort of emergency response would be sufficient to put the brakes on global warming. We can’t just shut down human industrial activity without billions of people dying, so it’s likely that we’ll just blunder about doing very little of consequence until nature lends us a hand and kills off a whole bunch of us.

People like Elon Musk and Jeff Besos want to go settle Mars and start humanity’s reach into space in ernest, but it’s unclear how that would really pan out given our terrible stewardship of the one planet we already have. Still I guess it’s worth a shot, but people are pretty fragile, and space is a pretty hostile place for people to be. I think it’s probably more likely that intelligent machines will go out and explore the universe. Maybe they’ll remember we invented them; maybe not.

Global pandemics, perhaps as a result of the release of prehistoric virii and pathogens from the melting permafrost, might take out a few billion of us, and the previously mentioned potential Greenland ice event would likely cull the human population by a significant percentage and reduce industrial activity, and thus greenhouse gas emissions.

There is still a significant amount of inertia in the climate system that’s simply going to play out anyway, with or without us. According to the IPCC we still have time to limit warming to 1.5°C, but to do so we, as a planet, need to reduce the amount of CO₂ equivalent in the atmosphere by 45% by 2050.

The wholesale cessation of deforestation, massive reforestation programmes, complete switch over to renewable energy, powering electic cars, planes, and ships, that use hyperefficient batteries, and the mass conversion of the planet’s omnivores to vegetarians, are all entirely laudable paths forward, and, long-term, if there is a long-term for us, they are all going to have to happen. There are not going to be a lot of beef eaters on a climate-ravaged Earth, or on Mars, or living in some sort of giant space station parked out near Jupiter, and no-one in the future is going to still use fossil-fuels to get around; that’s patently obvious.

The question is really, as Superchunk observed, “how fast?” Can we make this transition in time to prevent clathrate collapse or the popping of Yellowstone park? How many billions will die from famine, disease, water-shortages and toxic air pollution before we clean up the place? How many need to die before head-in-the-sand deniers get out of the way of those of us trying to make a difference?

To me a “climate emergency” means a war footing; and that means waging war against the deniers first, as they are the real obstacle. I’d be very happy to see a lot of our current senior political and corporate leaders hauled up in The Hague and charged with crimes against humanity, and I’d regard that as entirely appropriate. But that’s a fantasy and is, alas, unlikely to happen.

In various countries citizens are resorting to the courts to force their governments into action, and that’s certainly a pathway to progress in places where laws are designed to enforce the rights of ordinary people, rather than simply there to block action against climate change.

The sad truth is that almost no-one really believes that global warming, and the myriad other issues that stem from humanity’s abuse of the planet, are truly anything to get too worried about.

Most people I know, even those who completely accept that climate change is real and happening, continue to act as if they believe, deep-down, despite what they say, that the risks are overstated and, if impacts are going to be felt, they’ll be felt by other people and way in the distant, to them, future.

People may say that they accept the science, but they act as if they don’t. A lot of people subscribe to a kind of magical thinking, wherein some hitherto undreamed of technological fix will just make the whole problem go away, so we can just continue polluting.

The emergency is upon us. We must urgently and radically change the way we generate power, fuel, and food, while putting in place adaptation measures to deal with the global warming already locked into the planetary system. If we do hit the runaway global warming tipping point, then no amount of adaptation will be possible. But simply explaining the facts clearly is usually written off as being alarmist. And that’s the core of the climate crisis.


I have drawn links from a wide range of sources, avoiding political partisan websites in favour of sites that source actual facts, reports, or direct interviews. They are listed here in the order they appear in the article.


Thanks go to Dr Ross Williams for proofing this article, and for offering a much improved title to the one I started out with.

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Dave Sag

Written by

Dave Sag

Blockchain Tsar & Senior Javascript Practitioner at Industrie&Co. (https://industrie.co)

Age of Awareness

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Dave Sag

Written by

Dave Sag

Blockchain Tsar & Senior Javascript Practitioner at Industrie&Co. (https://industrie.co)

Age of Awareness

Stories providing creative, innovative, and sustainable changes to the education system

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