What causes climate change?

Earth’s temperature depends on how much of the sun’s energy is absorbed and how much is released.  If sunlight hits something light in color, it bounces straight back to space.  If it hits something darker, it becomes heat.  Some of this heat also escapes into space — how much depends on the composition of our atmosphere.  Gases like methane and carbon dioxide slow the escape of heat.  Methane traps more heat, but because it breaks down quickly, it doesn’t build up decade after decade in the same way that CO2 does.


In 1910, CO2 levels in the atmosphere were around 300 parts per million — today they are well over 400ppm.  A lot of our excess C02 is being absorbed by the ocean — this leads to ocean acidification which causes major problems for ocean life.  For example, it prevents shellfish from growing stable shells, making it impossible for them to survive!

Are we sure humans are causing climate change?

Yes!  Scientists can tell where different C02 molecules come from based on their isotopes — and this proves that much of the new the CO2 in the atmosphere comes from fossil fuel consumption.

Why do people say the world will end in 12 years?

That number comes from the United Nations Intergovernmental Panel on Climate Change.  In the SR15 report, released in November 2018, scientists were asked to model the difference between 1.5° and 2° of warming.  They found that conditions at 2° of warming would be much worse.  The 12-year estimate is based on the report’s finding that we must halve emissions in 12 years (and get to net-zero by 2040) if we want to keep warming at 1.5°.  The worst impacts won’t hit immediately in 2030 — but if we don’t cut emissions by then, we won’t be able to prevent 2 degrees of warming from hitting later in the century.

Is a couple of degrees of warming really that bad?

Maybe 2 degrees of warming doesn’t actually sound so bad.  But that is the average warming – the heat isn’t spread evenly around the world or throughout the year.  Warming can come in heat waves or concentrate in certain areas.  Some areas will become uninhabitable, creating millions of climate refugees.  Warmer air also holds more moisture and that means more rain in some places and droughts elsewhere.  There will be bigger hurricanes and more wildfires.  Slight temperature changes can have massive impacts on plants and animals.  We don’t exactly know how much warming it will take to push any given species to extinction.  And species depend on one another — so when one species migrates or dies, other species will also collapse.  Fish are moving further away from the equator every year.  Insect and plankton populations are ALREADY collapsing.  The rate of extinction is already thousands of times higher than normal — and so far, we’ve only seen about 1 degree of warming.

The IPCC previously aimed to keep warming ‘well under 2 degrees’ — but they didn’t have a clear understanding of what exactly the difference was between 1.5 and 2 degrees of warming until the SR15 report was released.


As you can see, coral will be completely wiped out at 2 degrees of warming.  Sea level rise will be much higher and crop yields will be much lower.  Heat waves will be longer as well — leading to more deaths from heat exhaustion.

The real problem, though, is that we aren’t even on track for 2 degrees of warming — scientists estimate that we are headed for 3 or 4 degrees of warming.  And those numbers could completely collapse civilization due to food and water shortages and  unprecedented losses in the real estate market.


But world governments are fixing it right?

No!  Not even close.  We are barely doing anything.  Emissions reached new all-time highs in 2018 and again in 2019 — when the science says they must be falling by 7% every single year.  This is despite treaty after treaty in which nearly every country on earth pledged to rapidly reduce emissions.

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This chart shows how fast emissions would have to fall (notice that they have to go BELOW zero!) to remain under 1.5 or 2 degrees of warming.  The purple band is the pledges countries made under the Paris Agreement (2.6-3.2C).  But most countries – including Canada – haven’t implemented policies to match their pledges, so the green band is the most likely outcome (3.1-3.7C) and the orange band (where billions of people either migrate or die) is still a real possibility.  Especially if we see more back pedalling of the type that is currently on display in Ontario, Australia, the United States and Brazil.

Another problem is the ‘production gap.’  Most international accords count emissions created within each country — but not exported fossil fuels.  Most fossil-fuel producing countries are claiming they can reduce their own emissions while cranking up fossil fuel production — somebody (or maybe everybody) is lying.


The United Nations has a beautiful website on the production gap that you should check out.

What’s a Carbon Budget?

Another way of looking at the problem is in terms of a carbon budget — and our budget is rapidly running out.  If we burn all the fossil fuels that we have already started mining (this doesn’t even include reserves that we have identified, but not yet developed!) — we will exceed the carbon budget for 1.5 degrees.  So if we are serious about cutting emissions we must stop exploring for new oil, gas and coal.


What’s the deal with feedback loops?

Feedback loops are natural processes that are triggered by warming AND lead to further warming.  When ice melts, it exposes darker earth and water, meaning less light is reflected back into space.  When the air gets really hot and dry, there are more forest fires and forest fires emit a lot of c02.  The unprecedented fires in Australia this winter (their summer) have already emitted almost 50% of Australia’s annual emissions!

When ice melts, it doesn’t suddenly grow back when temperatures stabilize — that takes thousands of years.  Forests can also be slow to recover — rainforests in particular struggle to grow back because regions become too dry without them.  Scientists are aware of these processes and some of them are captured in the IPCC models — but not all of them and some older estimates have been too conservative.  An article from November 2019 in Nature — one of the top scientific journals in the world — makes the case that newer, more accurate models are showing the chance of hitting irreversible tipping points at lower temperatures is much more likely than we previously thought.

tipping points chart

“If damaging tipping cascades can occur and a global tipping point cannot be ruled out, then this is an existential threat to civilization. No amount of economic cost–benefit analysis is going to help us.” (Nature, November 2019)  These authors argue that if these changes are irreversible and threaten humanity’s very existence, then we must prevent them no matter how much it costs.  This is a scientific way of saying: ‘there are no jobs on a dead planet’.  

We’re still at ‘OOPS’ but ‘Fuck’ is approaching very, very quickly.

But aren’t we dependent on fossil fuels?

Not really.  We can’t go to zero-emissions overnight of course, but there are technical solutions available on the market for most sources of emissions except long-distance air travel.  Many of the best solutions are practices from other decades and centuries — bicycles, streetcars, indigenous land management practices.  Rewilding and expanding and preserving mangroves and peat bogs could draw down huge amounts of carbon from the atmosphere!  Reducing the amount of meat and dairy we eat will reduce methane emissions — and it’s good for our health.  We can use heat-pumps to heat and cool our homes with less energy and no fossil fuels.  We also know how to make houses that are so well-insulated they don’t need a furnace, even in Canada.

This home has no furnace!

Producing cement has very high emissions, but we’re learning how to make tall buildings with cross-laminated timber — which is carbon negative if the forests are managed properly.  Difficult problems like generating the high temperatures needed for making steel are being reengineered.  For a full list of solutions check out Project Drawdown.

Unfortunately, all these technologies are still the exception rather than the rule.  As much as we hear news about growth in renewable energy, the real story is that energy use is growing overall, so coal, oil and gas consumption are ALSO growing.

What should governments be doing?

We need policies that eliminate the dangerous practices and scale-up the safer ones — and we need them in place immediately.  For example, many countries have set a date after which it will be illegal to buy or sell gas-powered automobiles.

There is some debate about whether we need carbon pricing or a ‘green new deal’ that kick starts a government-led mobilization to build low-carbon infrastructure.  In our eyes, this debate misses the point.  A Green New Deal is going to need carbon pricing to handle the nitty-gritty that can’t be centrally-planned. Aggressive carbon pricing is going to require public investment in infrastructure so people aren’t left behind by a rapid transition.  We need both!  So let’s just get on with it.

Why Haven’t We Fixed it Yet?

A major cause of our inaction is misinformation initiated and funded by fossil fuel companies — who hired many of the very same PR experts who spent decades leading people to believe that cigarettes didn’t cause cancer.  But another part of the problem is that our brains tend to focus on more immediate challenges and we often have little time in our day for a problem as large and complex as climate change.  We know it’s a problem, and yet we just going on repeating the very same patterns of activity that got us into this mess — making deposits in the same banks, voting for the same parties, driving the same vehicles, eating the same foods.

All of that has to change and it has to start now.  But your brain prefers to just follow along with long-standing habits unless they are completely unavailable.  Each and every one of us must schedule some time to reasess our daily lives and get involved in driving policy changes.

What about Climate Justice?

The Climate Justice movement is motivated by the fact that those who have done the least to cause this crisis are also most likely to be negatively impacted.  This applies both globally and within countries.  Smaller countries in Africa, South Africa, South Asia, the Pacific and the Caribbean have very low historical emissions but will bear the blunt of future climate disasters and sea-level rise.  Within countries, wealthier people have much higher carbon footprints, but can more easily afford to maintain their lifestyle in an unpredictable climate.  On the other hand, children, the elderly, racialized groups, outdoor workers, people living in basement apartments and other equity-seeking groups are more likely to be negatively impacted by heatwaves and floods.  Climate Justice also, typically, includes a just transition for workers who have operated and built our fossil fuel infrastructure, often at great personal risk, and could suddenly be out of work if we decarbonize rapidly.  At an even deeper level, indigenous people have historically been the best environmental stewards and, because of their connection to the land, they have the most to lose to forced migration, changing weather and wildlife.  All around the world, indigenous environmental activists are still being murdered by governments and corporations because they stand in the way of drilling and mining projects.  Colonial attitudes to land and resources are at the core of our current crisis — we cannot continue to think of our planet as a heap of assets to be dug up, processed and exported.  Naomi Klein refers to this dangerous mix of colonialism and capitalism as ‘extractivism.’  We must return to a way of life that nourishes and rehabilitates the land that supports us — and indigenous people can help guide us along this path.

If you’re ready to take action click here!

If you still think it’s all a big UN hoax, please read on.

Does all the evidence come from the United Nations?

Nope.  We’ve known about climate change from burning fossil fuels for around two hundred years – about 100-150 years more than the UN!  In the 1970s and 80s Exxon started researching the impacts of global warming — and their research turned out to be pretty much bang on:

015-exxon-carbon-co2-prediction-1A lot of our best evidence about climate change does come from the United Nations.  That’s because the intergovernmental panel on climate change (the IPCC) is compiling research from more than 10,000 scientists around the world.  These scientists aren’t paid by the UN — they mostly work for universities and other independent scientific institutions and contribute to the IPCC alongside their other work.

But it’s not just the UN sounding the alarm on climate change.

MunichRE a major player in the drop-dead boring, largely apolitical, reinsurance industry says “climate change, predominantly the result of human activity, is real and has a major influence on weather-related natural disasters.”  The reinsurance industry cares because if the floods and fires get bad enough that insurance companies start collapsing — they will be left holding the bag.  A recent US Army report highlighted the risks of rising migration and conflict, water scarcity, food shortages and the possible failure of the US power grid.  A 2019 Goldman Sachs report focusses on flooding, extreme weather, food and water shortages and major risks to the property market.

But what about India and China?

What about them?  India and China will have to find ways to reduce their emissions too — but that doesn’t have much bearing on whether or not we should reduce ours.  India and China have no incentive to decarbonize if wealthier European and North American countries don’t take the lead.  On a per capita basis, emissions are far, far higher in North America and Europe than they are in China.  And per capita emissions are what matters most — otherwise China could simply reduce its emissions by splitting into regions (which is a ridiculous idea).  Furthermore, China and India are still trying to lift people out of poverty — if we refuse to reduce our emissions from a position of wealth and privilege why should they make an even greater sacrifice?  Likely the fastest way to get emissions reductions in China and India is to lead by example and share the practices and technologies that are most helpful in bringing our emissions down.


And that’s the end of our crash course in climate change — let’s try to avoid crashing our planetary life support systems!  Click here if you want to take action.