The Consequences of Climate Change
| 1 - Climate Changes of the Past
2 - Climate Change Today
3 - Climate Changes in the Future
4 - How Bad Can it Get?
5 - Footnotes and References
Climate Changes of the Past
The earth's climate has changed many times over the billions of years of its existence. Normally, the changes have been slow - occurring over tens of thousands of years. When things change slowly, life has time to adapt and change with the times. However, occasionally, the changes have been swift, such as when an asteroid struck our planet around 65 million years ago. In that case, the dust raised from the impact quickly cooled the world for several years, and this sudden climate change resulted in the death of 75% of all species living on earth, including the dinosaurs, leaving an ecological niche for mammals to exploit. Alternate theories propose that the impact actually released a lot of CO2, and raised temperatures 7C or more, which lead to the dinosaurs demise.
Sometimes the climate changes were not quite so sudden but happened over hundreds of years with equally deadly results, such as what happened 251 million years ago when the earth looked a lot different. All the land was gathered into one supercontinent. Sustained volcanic eruptions in what is now Siberia released prodigious amounts of sulphuric acid and carbon dioxide, extinguishing 96% of marine species and over 70% of all land species! This was the single largest extinction of life that has ever occurred on our planet. We are not exactly sure of the cause of this event - some evidence links the extinction to an initial small global warming, thanks to the volcanic release of CO2, which led then to massive releases of the vast stores of methane in the soils and the oceans. This accelerated the moderate global warming already underway. Methane is a very potent greenhouse gas, 23 times more powerful than carbon dioxide. It may have been these methane "burps" that caused the greatest mass extinction of all time.
There have been 5 major mass extinctions of life on our planet, where over half of all species alive at the time were destroyed. Today, we are witnessing a 6th mass extinction. Forecasts estimate that, within 100 years, 50% of all species will be gone. Unlike all the other past mass extinctions of life on our planet, this extinction is not caused by mother nature, but by her most precocious child, us.
Climate Change Today
We know that our climate has changed dramatically in the past and sometimes with devastating consequences. But is our climate really changing today? The short answer is - yes! Today, the average temperature of the surface of the earth is about 14.7C; that is almost 1C warmer than 100 years ago. Of course 14.7C is just an average: an average of day and night, of summer and winter, of northern latitudes and the equator, of a Toronto July day and a Yellowknife January night. It is very hard for us, as human beings to notice a 1C change in average temperature by our sense of feeling. But a change from 13.7C to 14.7C is definitely noticed by our biosphere. Just think of the difference 1C can make in the state of water: one moment frozen solid as ice, and then at 1C warmer, liquid. While we can't notice a 1C change easily, nature can and does.
Here in British Columbia, like the rest of the world, we have been warming up. Most of the province has been experiencing decadal temperature increases of .1C or more. This means that our average daily maximum and minimum temperatures are steadily increasing, especially in the winter and spring. In recent decades this rate has increased much more than before.
As the winters have become milder, the larvae of the Pine Beetle have been surviving in record numbers. Without the colder winters to freeze and kill the larvae, more Pine Beetles survive to decimate our forests.
The result has been the infestation of 14.5 million hectares of forests. We have been losing twice as much lumber to the beetle than we harvest. Forest Ministry estimates that the beetle will have wiped out 80% of B.C. forests by 2013: this is having economic implications for lumber communities in B.C. and tens of thousands of families. But the impact is not just to the lumber industry. In an article published in Nature, Canadian Forest Service scientist Werner Kurz estimates one billion tonnes of carbon dioxide will be released between now and 2020 due to the death of these trees, making climate change even worse.
With fewer trees, the snow packs melt more quickly increasing the likelihood of flooding in springtime and drought in late summer. The extent of the damage goes beyond the B.C. borders. Similar insects, such as the Spruce Bud Worm, are attacking the forests in Alaska and the Northwest Territories. The pine beetle has already begun its invasion of Alberta. Since the pine beetle has now breeched the barrier of the Rocky Mountains, it threatens the entire boreal forest, which reaches all across Canada.
In an August of 2009 report in Nature, climate researchers examining ocean sediments have discovered that warmer Atlantic temperatures have increased the number of hurricanes from a low of about 7 or 8 hurricanes per year in an average, cooler decade to 15 today. While the interplay of La Nina and El Nino can moderate these numbers, the trend is pretty clear: warmer temperatures means more hurricanes and more dangerous hurricanes. Hurricane Katrina in August of 2005 and Cyclone Nargis, which struck Myamar in May of 2008, caused severe flooding, billions of dollars of damage and tens of thousands of deaths.
With rising temperature, comes more frequent, longer and hotter heat waves. In the summer of 2003, a record heat wave struck Europe, killing 35,000 people; 14,800 in France alone, mostly elderly.
The average warming over the past century of about 1C is just an average. In the northern latitudes, the increase has been much higher. With the north warming quickly, the permafrost upon which much of the houses and transportation infrastructure was built, has begun to thaw. As the ground gives way, from Siberia to the North American Arctic, homes and even entire villages have been damaged. A big concern is what will happen if oil pipelines, such as the Trans Alaska Pipeline carrying millions of barrels of oil per day across 800 miles of tundra, rupture.
Our climate has already changed significantly, and has already caused severe local economic hardship and tens of thousands of deaths. Climate change is not just a remote, foreign problem anymore. Global climate change has a very local and real face.
And, it is going to get worse ... potentially, much, much worse.
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Climate Changes in the Future
What might future climate change do to us? The Intergovernmental Panel on Climate Change, the co-winners of the 2007 Nobel Prize, along with Al Gore, showed in their 4th Assessment Report, released in September of 2007, a number of possible futures. These 2,500 scientists from all over the world, using only published, peer-reviewed scientific studies, created several families of scenarios, varying by future population growths, technological advances - or not, and government political actions - or not.
In all 40 possible scenarios, the temperature rises this century. In the best case, if we had stopped all greenhouse gas emissions in the year 2000, the temperature would still rise more than .5C this century. This much warming is already in the pipeline, due to the slow responses of the oceans. This "no emissions" scenario is highly unlikely. Most scientists believed that the most likely scenario is A1B. A1 assumes that the population growth is at the low end of the range of possibilities: that we grow to 8.7 billion people by mid-century and then start to decline to around 7 billion by the end of the century. B assumes that we adopt clean technologies and reduce consumption.
As you can see in the graph, in the A1B scenario, the temperature will rise by an average of about 2.8C this century, but there are error bars on the estimates. It could be as low as 1.7C or as high as 4.4C. There are other scenarios that would take us to over 5C! Notice, for a moment, the error bars on these scenarios. Scientists keep track of the potential errors in their models and measurements. However climate change skeptics like to jump on this and claim that there are uncertainties in the science, therefore global climate changes shouldn't be worried about. That is a magician's trick of diverting attention away from what is actually happening. Yes, there are errors in the models: we know that, but that is not a good reason for discarding the whole estimate range. The results are going to be somewhere in that range. If the skeptics do not like the most-likely estimate and want to argue where in the range the result is more likely to lie, fair enough. But to say that there is no problem because there is a range of possibilities is dishonest.
The average increase of 2.8C in scenario A1B is just an average. Here is what it would look like around the world. As we have already seen by what is happening today in the Arctic, the actual increase varies considerably by latitude. The further north we go, the hotter it gets. In the Arctic, the temperature increase would be over 7C more, on top of the 4C that has already occurred over recent decades. That is a real problem for many reasons. Not only does it mean that the permafrost would no longer be frozen, affecting much of the infrastructure, roads and houses built upon it, but it also means that vast quantities of methane current frozen in the soils and peat bogs will be released. This is a potential positive feedback mechanism that has scientist very concerned.
Remember the methane burp 251 million years ago that may have caused the worst mass extinction ever? Scientists are very concerned that we may soon reach a tipping point in the frozen north, where the methane there is released, and starts a run-away greenhouse warming. If that happens, it won't matter anymore what we do, the climate will tip, the earth will warm and even if we reduce greenhouse gas emissions to zero, it will be too late.
The IPCC cannot predict how warm we will get, because so much depends on what we, as individuals, and what we demand our governments, do in the next decade. What the IPCC has done is to establish what will happen at different potential temperatures. This chart shows a range, from 1C of warming to 5C, and the range of impacts these increases will have. What is not included are positive feedbacks from methane releases, Arctic ice cap disappearing, increased clouds and water vapour, and other positive feedbacks, any of which could lead to a disastrous tipping of the climate.
The IPCC looked at five key areas; the impact on water availability, the whole ecosystem or biosphere, impact on food, sea levels, and health.
The IPCC report is quite scary when you learn what is happening to glaciers all over the world. Historically, glaciers come and go, they ebb and flow. Some types of glaciers around the world, tidal glaciers or surge glaciers, are growing. But since the 1700's the main glaciers in every continent are receding. As this graph shows, the shrinking is dramatic ... by thousands of meters. Here in Vancouver, where we don't get any of our drinking water or irrigation water from glaciers, this doesn't sound so scary. Fewer glaciers may mean our beer is not as mountain fresh, but - what's the big deal?
But let's go to the other side of the world for a moment ...
Below is a glacier in the Himalayas, as seen by a NASA satellite. It is the Gangotri glacier, which is the source of the famed Ganges River. Notice how the Gangotri has been shrinking, and up to 2004, this shrinking was accelerating. Today, the retreat of the Gangotri has paused, but for how long no-one really knows. (The dispute over the pace of Indian glacier's retreat is discussed in a November, 2009 Science article.)
The Ganges river provides life sustaining water for over 400 million people. According to a U.N. climate report, these Himalayan glaciers that are the sources of the Ganges could disappear by 2030 as temperatures rise. The rivers with headwaters in the Himalayas may become seasonal rivers. We are hearing similar predictions all around the world from the Alps to the Andes. A Chinese glaciologist (Yao Tandong), predicts that two-thirds of China's glaciers will be gone by 2060 ... but he was working with older data. It may not take that long.
Over 1 billion people rely upon the waters from the Himalayas. Where will these people go? What will they do when the waters dry up? We know from recent experience in Africa, people will not stay put when their lands have dried up. They are going to move. Can Asia cope with over 1 billion water refugees?
Sea Level Rise
Sea levels have already risen over the last century, causing problems for low-lying lands and islands. The IPCC has determined that Greenland will melt, just not for several centuries. More recent studies have shown that it could be a lot sooner. As the satellites images show, the season thawing of ice in Greenland is expanding. If all of Greenland melts, which it has several times over the history of the earth, sea levels will rise by 7 meters.
While it is unlikely that Greenland, or even worse, Antarctica, will be gone this century, the impacts of even a 1 meter rise in sea levels, combined with storm surges, will cause a lot of economic and human hardship. Although the prediction from the IPCC is that it will be a couple of centuries before Greenland is ice free, the IPCC doesn't include all the positive feedback mechanisms and tipping points. They couldn't model them, so they didn't include them.
Sea level changes have already happened. Arable lands have been rendered unsuitable for crops due to salt contaminating the water tables. Thousands of people around the globe have been displaced due to storm surges and coastal erosion caused by the rising seas. The government of Tuvalu have asked New Zealand to accept their entire population, should their land, which is only 1 meter above sea level on average, be submerged. We will be seeing more "climate change refugees" in the future.
But even more worrying to scientists than the loss of land based glaciers, is the coming loss of the whole Arctic ice cap by the end of each summer. The Arctic ice sheet has importance beyond what it means to the animals and people living in the north. Sea ice occupies 7% of the surface of the earth, and as you can see, it is nice and shinny white. Sea ice reflects 80 to 90% of the sunlight striking it back into space, and it helps to keep the waters beneath it cool, like a blanket keeping heat out of the seas.
The image shows what happened to the ice sheet in 2007. The tan colour shows the normal, average size of the ice sheet in the summer, which is around 7.3 millions square kilometres. In September of 2007, there was only 4.1 millions square kilometres ... we are losing the summer arctic ice. When the winter comes, the ice forms again and covers the whole region once more, however now ... the ice is all new ice. Previously the ice was thick multi-year ice that even our biggest icebreakers had trouble cutting through. Year old ice, new ice, is easy to break and melts away faster than multi-year ice. This means that next summer, the sun will have less difficulty melting away more and more of the ice sheet. Where there was once ice, will be open ocean. Instead of reflecting 80 to 90% of the sunlight, the open ocean absorbs 80 to 90% of the sunlight, warming up the water, creating the positive feedback loop we discussed earlier. With warmer Arctic waters, Greenland will melt faster.
While 2007 was a record for the smallest surface extent of the Arctic ice, 2008 set a record for the smallest volume of ice, due to its thinness.
When will the ice sheet go away completely? The IPCC says gone this century. NOAA in 2003 said, gone by 2080. The Ice and Snow Centre in the USA in 2006 predicted gone by 2040! A year later, in 2007, the Ice and Snow Centre revised its estimate and found that it could be gone by 2012! Fortunately, we won't see the arctic ice free this decade, but we won't be waiting for the original IPCC prediction of 2080. Things are happening faster than we thought.
Impact on Food
Studies in China and the Philippines have shown that as temperature rise beyond a certain level, rice production decreases. Plants, when it is too warm, shut down photosynthesis: instead of taking up carbon, they begin to emit it. Pollination also totally ceases once the temperature reaches 40C. The net impact, according to the IPCC of climate change is a 10% drop in food production as we warm up by 1C!
And it is not just temperature changes that will stress our ability to produce food. The rising seas will also inundate and salinate fertile lands. One half of Bangladesh's rice crop will be destroyed if the sea level rises 1 meter. It takes 1,000 tons of fresh water to grow one ton of grain. A lack of fresh water will heavily impact food production: water stress is already showing up around the world from California to Northern India. We have already seen how many of the world's glaciers are drying up, meaning less irrigation, meaning less food.
UN World Food Programme reports that 18,000 children die every day due to hunger and related causes. That's over 6.5 million kids a year dying of hunger!
As a society, we were making pretty good progress on starvation and malnutrition ... good up until about 1996. Here are the statistics from the UN Food Programme of the number of hungry and malnourished people in our world over the last few decades:
960 million in 1970
800 million in 1996
830 million in 2003
1.02 billion in 2009
1.2 billion by 2025
In the scenario being considered, A1B, the IPCC is forecasting that our population will rise from over 6 billion people today to almost 9 billion by 2050. With less food available, how are we going to feed 9 billion people in 40 years? This forecasted number of 1.2 billion hungry and malnourished by 2025 will soon be far exceeded.
Impact on Health
The changing climate is going to have considerable consequences on our health in many ways. Here is a portion of an email I received from one of the IPCC scientists describing the impact malaria is and will have as temperatures rise, and explaining why Bjorn Lomberg's book, Cool It, is mistaken in saying that we have nothing to worry about from mosquitos ... he was talking about the wrong kind.
There are two primary forms of malaria (vivax and falciparum). Vivax is a milder form of malaria, with low death rates. It is carried by a mosquito that is indifferent to whether it bites humans or animals. This is the form of malaria that was historically prevalent in the US and Europe. It caused significant morbidity among all ages, not just the young and poor. And it started to decrease in prevalence as people became wealthier, building their own houses separate from their animals (the malaria control efforts came much later). In the South of the US (where it was a large problem), just moving people up a small hill away from their animals made a significant difference. As an aside, this is the reason that the US Centers for Disease Control and Prevention is located in Atlanta; the Federal government wanted the agency to be based near one of the major health problems of the day. The last outbreak of malaria in Europe was something in the 1950s, as I recall...
The other form of malaria, falciparum, is the form that is common in Africa. It kills 1.5-3 million people annually. It is carried by a mosquito that strongly prefers to bite humans and will travel distances (up to a mile) to do so. So, moving animals away from houses has little impact. There are regions of Africa where people receive 2000 infective bites annually. Africa has a history of failed malaria control problems (at least 100 years of various initiatives). It is very difficult to control. Most of the large population centers in Africa are in highlands precisely because of diseases like malaria; they were established above the areas where malaria has been a problem. However, climate change is providing opportunities for the mosquito to move to new regions. There are reports of malaria moving up highland areas around the world, from Africa to the Himalayas. People who are chronically exposed to malaria develop a low-grade immunity. They may suffer multiple episodes of malaria annually, but it generally doesn't kill them (that is why the 1.5-3 million annual deaths are mostly in children). When malaria appears in an area where people don't have immunity, the mortality rate can be as high as 30%, and deaths occur across all age ranges. Imagine malaria appearing in some of the major cities in Africa; it would have a large impact on societies. .
Mosquitoes spread other diseases too, such as West Nile disease and Dengue Fever. The IPCC predicts that by 2085 climate change will put 3.5B people at risk of dengue fever. Like many of their time estimates, it probably won't take that long. In August of 2009, British Columbia recorded its first case of West Nile disease, according to the B.C. Centre for Disease Control.
Impact on Biodivesity
Rainforests use to cover over 12% of the surface of the planet. Today they cover only 6%! Rainforests house over half of our plants and animals species. They are important, but one of the reasons the CO2 level has risen so dramatically over the last century is our habit of turning rain forest into carbon. We are converting 50 million acres a year into carbon and putting that into our air.
As the level of CO2 rises in our atmosphere, it also increases in the oceans. In the ocean, extra CO2 increases the level of an acid called carbonic acid. As CO2 levels rise, the ocean becomes more acidic. Everything that makes a shell is threatened by increased carbonic acid in the ocean. That includes many types of plankton! Once we lose the bottom of the food chain, the whole chain starts to collapse. [To learn more, view this video to see how dangerous rising CO2 levels are to the health of our oceans: Acid Test: The Global Challenge of Ocean Acidification]
Coral covers less than 0.2% of the ocean floor and yet our coral reefs contain around 25% of all marine species. Current forecasts by the Environmental Defense Fund state that 60% of all coral reefs could be lost in the next 20 ~ 40 years!
The current pace of extinctions is 1,000 times faster than historical rates. The 2006 U.N. Global Biodiversity Outlook 2 reports that in jeopardy today are
22% of the world's mammals,
30% of reptiles,
39% of fishes,
31% of amphibians,
22% of birds,
70% of the world's assessed plants
At the current rate of species lost, 50% of all species will be gone inside 100 years, placing our generation in the midst of the 6th largest mass extinction ever to occur on earth. This is not due entirely to global warming, but global warming is a significant contributer to massive extinction of life happening today.
The IPCC research has shown that even just a 2C rise in temperatures this century (over the average of the temperatures in the period of 1980 to 1999) will result in many significant problems.
At 2C we lose 20% of our food crops
At 2C we put at risk 30% of all species on the planet
At 2C we could raise sea levels by .5+ meter
At 2C most coral around the world is wiped out
At 2C we may tip many positive feedback loops
- The Arctic ice is gone in summer, making the whole planet warmer,
- More water vapour enters the atmosphere, making the whole planet warmer,
- 15% of the land will stop absorbing carbon and will start emitting it, making the whole planet warmer.
A 2C warming is not a good idea! We don't want to risk all these problems, nor do we want to risk tipping these positive feedback cycles. If they start to tip, then the climate will start to warm all by itself, and it won't matter what we do. Even if we reduce our carbon emmissions to zero, these new sources of climate change will overwhelm anything we do. The climate will cyclically warm up to dangerous levels, and we will be unable to do anything about it.
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How Bad Can It Get?
So, what is the worst that could happen? Yes, we have heard a lot of different scenarios: they all seem bad, but just how bad could it get? At 5C, the top range of the IPCC chart shown above, some very serious impacts hit every part of the globe.
- Billions of people become water refugees
- Sea levels rise 1 to 5 meters or more, creating hundreds of millions more refugees
- Disease from poor water and insects rise dramatically
- Food production drops by 50%
- Famine and war erupt across the globe
- Economies fail: hyper-stagflation becomes the norm
- Other positive feedbacks release the stores of methane in the soils and oceans, causing a run-away greenhouse effect!
The End of Civilization as we know it?!
All this can happen, not only in your children's life time, but perhaps even within your own lifetime. Nowhere on the planet will be free from these effects. It will be a global meltdown of civilization...if the worst happens.
But, come on! What is the likelihood of this worst case scenario happening? I mean...what are the odds here? Sure there is a chance that the worst could happen, but there is also a chance that mutant space gerbils from Alpha Centauri will attack and devour the earth. Should we spend trillions of dollars to create a mutant space gerbil shield for the earth? Since the odds are so tiny of an attack, surely we don't need to protect ourselves from this threat?
That's a fair question! What are the odds of a 5C increase in temperature occuring this century?
Well, fortunately, the fine folks at the Massachusetts Institute of Technology (MIT) have done the work for us and can tell what the odds are. In 2001 the MIT Joint Program on the Science and Policy of Global Change created the Great Greenhouse Gamble (TM) pinwheel. Step right up, ladies and gentlemen and place your bets!
The 2001 Greenhouse Gamble Pinwheel
The wheel depicts the MIT Joint Program's estimation of the range of probability of potential global warming over the next hundred years, assuming a scenario in which "no policy" action is taken to try to curb the global emissions of greenhouse gases. The face of the wheel is divided into eight slices, with the size of each slice representing the estimated probability of the temperature change in the year 2100 falling within that range. Note here ... that there is only a 36% chance that temperature rises will be 2C or less ... which means that there is an 64% chance that the temperature will be higher than 2C. Also notice that there is a very real chance, 3.8%, that the world will warm up by more than 5C ... that is the ultimate danger zone ... no wonder they painted it red.
The most likely values predicted by the MIT Program for warming under this sample policy scenario are;
>5C - 1 in 26 3.8%
4 - 5C - 1 in 22 4.6%
3 - 4C - 1 in 6 16.2%
2.5 - 3C - 1 in 6 16.8%
2 - 2.5C - 1 in 4 22.5%
1.5 - 2C - 1 in 5 20.6%
1 - 1.5C - 1 in 9 11.4%
less than 1C - 1 in 24 4.1%
In 2001, the MIT researched worked out that there is one chance in 26 that the worst will happen: that we will warm up 5C, which means we will see the end of our civilization this century. A 3.8% chance is quite significant. Virtually everyone who owns a home buys house insurance just in case of the one chance in a 100,000 that their house will burn down or be otherwise destroyed. They buy this insurance because the alternative is just too risky. The loss of a family home could mean economic ruin. It is not worth taking the risk.
Put this risk another way: if you were told that there was a 3.8% chance that your airplane flight was going to crash and everyone on the plane die, would you board that plane? I didn't think so...
Risk Revised --- 2009
Okay, if you are a normal person, you won't board a plane that has one chance in 26 of fatally crashing, and you certainly wouldn't put your kids on that plane. But those are the odds as worked out in MIT back in 2001. We have had 8 years to watch the climate unfold since then, to discover new trends, to refine our climatic models. What are the odds today? Here is the 2009 version of the pinwheel. Did things get better? Or worse?
The 2009 odds
>7C - 1 in 11 9%
6 - 7C - 1 in 7 15%
5 - 6C - 1 in 3 33%
4 - 5C - 1 in 3 30%
3 - 4C - 1 in 8 12%
less than 3C - 1 in 100 1%
Worse ... much, much worse. Today's research has determined that the odds of our climate warming by 7C is 11%. Seven degrees?! We never even talked about 7C before! The chances of our world warming up by 5C or more is now 57%, if we do nothing about it. Unfortunately, we are doing nothing about it. We are facing a world in the very near future that has a greater than 50% chance of seeing the end of our current civilization.
To return to our earlier analogy: would you let your family, and everyone you care about, and everyone you know, board a plane that had a 57% chance of crashing? Many people feel today the same way some Romans or Mayans must have felt as they saw the coming end to their civilization. All things must end. Our civilization will end one day. But it doesn't have to be today! It does not have to be in our lifetime.
Do we do anything about this or not? Listen to the skeptics and it sounds like we have nothing to worry about. But, what are the odds that they are wrong? Have they worked the probabilities, as the climate scientists have? Are the skeptics 100% sure that they are right? Even there is a 1% chance that they are wrong, that is a risk we should not be taking. Notice again the latest pinwheel from MIT. The best scenario they have is that we will warm up by 3C or less, and the odds of that are 1%. There is a 99% chance that we will see the climate warm up by 3C or more in our children's lifetime. Remember, even a 2C warming is not good.
If this analysis still fails to motivate us to make the changes we need to make, perhaps this video will. This is an excellent 10 minute analysis. It is entertaining, scary and moving. It is worth watching and forwarding to as many people as you can.
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