So this is it, we’re all going to die

Ok, so we’re not really all going to die – not yet anyway – but the IPCC did release Part II of report number 5 last week and there’s lots in it which should be cause for concern. The first part – released last year – was about the science of climate change. This one is about Impacts, Adaptation and Vulnerability. Contributing to this report were 243 lead authors from 70 countries as well as 50,492 comments and over 12,000 scientific references cited.

I’ve been wanting to write something about it but thought I should read it first. However it’s very long and I may never read it in its entirety, so to steal the words of Sydney Smith:

I never read a book before reviewing it. It prejudices a man so.

I’ve skimmed the first 7 chapters and pulled out some important points but left many others. I’ll write about the other chapters in a subsequent post. This section is about the impacts of climate change on natural and managed resources.

Climate change will increase the frequency of droughts, floods, heat waves, tree mortality (already being observed) and forest dieback, and will negatively affect freshwater ecosystems. There will be more heavy rainfall events, glaciers will continue to melt and the frequency of landslides is expected to increase. Sea level rise (projected to be in the range of 0.28-0.98m by 2100) will contribute to flooding and erosion; storm surges will get worse; ocean acidity will increase as will the temperature of coastal water which is bad news for coastal ecosystems and the communities that depend on them. Coral reef ecosystems are particularly vulnerable and have few adaptation options.

There is increasing risk of species extinction and this has possibly already begun (e.g., central American frogs). Plants and animals will move towards cooler regions – the poles and higher altitudes – and in some cases are doing so already. But some species will not be able to move fast enough and some habitats may disappear altogether. Fish will continue to move towards cooler water which will be beneficial to some commercial fisheries at the expense of others and as always seems to be the case, it’s the poorest regions of the world that are the most vulnerable.

Some plants will grow faster with higher levels of CO2 – but only up to a point – and some will also use less water. But this enhanced growth will be at the expense of important nutrients resulting in poorer quality food. There is also some evidence that enhanced tree growth from increasing CO2 has already peaked in many places. Once the temperature hits 1°C above preindustrial (and we’re currently at about 0.8°), the yields of major crops – wheat, rice, maize – are projected to be negatively affected (although some regions may individually benefit). Hot nights are already having an impact on rice yields and rice quality.

Warmer temperatures are causing invasive insects to spread, like the mountain pine bark beetle. Spring events like breeding, budding, flowering and migration are changing and starting earlier. Climate change has also contributed to the spread of viruses and ticks that affect livestock.

Ecosystems in the tropics and the high latitudes are particularly at risk. In the tropics this is because the plants and animals there have evolved within a limited temperature range and in many cases are already at their maximum limits. In the high latitudes, species are at risk because the projected temperature change will be large.

It’s possible that deserts will expand, despite increases in rainfall on the earth overall. They will also become hotter and dryer.

The Arctic is warming faster than the global average and this is affecting animals there. According to the report, seven of 19 subpopulations of polar bear are in decline, while four are stable, one is increasing and there’s insufficient data on the remaining. It is expected that their numbers will dramatically decline as the Arctic warms.

Frozen soils and permafrost hold more than twice the amount of carbon in the atmosphere. When they melt, they release carbon and methane and so present an additional threat and source of greenhouse gases.

The next six chapters relate to humans so I’ll save those for next time.

 

20 thoughts on “So this is it, we’re all going to die

    1. AV,
      It won’t be a major extinction event if we starting making changes soon. If we stupidly continue with business as usual then the risk is real.

      1. No AV, it’s not too late already. What we do over the next decade will be crucial though and the longer we leave it before doing something, the more expensive it becomes and the harder it will be. It’s true that we’ve already locked in a certain amount of future warming but we can still limit this to 2C if we take action. If we don’t, we’re looking at 4C by end of century.

  1. Rachel, what the report doesn’t say: If we don’t arrest or dramatically limit the amount of C02 emissions immediately (fossil fuels; heating our homes, driving our cars) the average earth temperature will rise above 3 degrees and yes, as a species, we’re done. It’s not the little guy anymore..it’s Obama saying no to Keystone XL and speeding up the conversion to renewable energy sources. The US is in the top 5 countries and probably # 2 for carbon footprint per million population. Susanne http://www.4thenextgeneration.ca

    1. Susanne, I agree. As I said to AV above, we’re looking at a possible 4C by end of century under business as usual. But it doesn’t have to be this way. There are a number of good strategies on the table for dealing with this, one of which is a carbon tax and yet I see countries like Australia, which emit far more than their fair share of greenhouse gases, doing the inexplicable and repealing the carbon tax. Thanks for the link.

    2. China has just surpassed the United States as the number one polluter in the world, but on a per capita basis, the US is still leading them by about 5 to 1. And yet many of our politicians cannot see why we need to take steps to reduce pollution even though China may not follow. It seems that China may be more serious about it than we are,as they seem to realize it is a problem and do not have the entrenched fossil fuel companies to tell him it isn’t.

      1. If the US adopts a carbon tax then China may be forced to follow because the US could implement some kind of trade tariff or trade ban on imports from countries that do not have a similar tax. If China went first they could do the same thing and force the US to join as well. We really just need one of them to do it and the other will follow.

  2. Even if the more conservative estimates of transient climate response are correct, the likely prolonged transition away from FFs will probably mean 1C – 2C increase in average global temperatures by the end of the century. But it is the speed of the change that catches ecosystems out. 0.8C C19th – C21st. Another 1C – 2C by the end of the C21st (if we are very lucky). That’s a lot of warming very quickly. Too many organisms are incapable of adaptation (including migration) to abrupt (eg. centennial) change. For example, it’s very difficult to see how rapid shifts in temperature, salinity and pH will not destabilise marine ecosystems at a global scale.

    I don’t think it’s “alarmist” to point to a mass extinction of marine flora and fauna as near-inevitable at this point. This is not to say that the ocean will become devoid of life. Rather that the diversity will be hugely and sharply diminished in ways that are unlikely to be a Tolian positive. I find this hard to bear thinking about, and we haven’t started on terrestrial ecosystems and the geopolitics of resource scarcity.

  3. BBD,

    I don’t think it’s “alarmist” to point to a mass extinction of marine flora and fauna as near-inevitable at this point.

    It’s certainly a risk, and so I don’t think it’s alarmist to say so, but I think a mass extinction on the scale of the Permian extinction is unlikely, unless we continue with business as usual. Here’s what chapter 6 of the report has to say about it:

    For millions of years in Earth history, natural climate change at rates slower than today’s anthropogenic change has led to significant ecosystem shifts (high confidence), including species emergences and extinctions (high confidence). Contemporary multidecadal natural climate variations associated with regional transient warming periods by 1°C have led to fundamental restructuring of ecosystems and large socioeconomic implications (high confidence). [6.1.2, 6.3.1, 6.4]

    Global-scale collapse of marine ecosystems is rare, even in the geological record. Some mass extinctions, in particular the Permian Period extinction 251 Ma ago, have been associated with large-scale inputs of carbon into the atmosphere and ocean, with associated warming and deep-sea O2 decline (Knoll et al., 2007; Kiessling and Simpson, 2011). The end-Permian mass extinction preferentially affected reef organisms such as corals and sponges resulting in a 4 Myr period without reef builders (Kiessling and Simpson, 2011), and underscores that vulnerabilities differ among organisms depending on anatomy, physiology, and ecology (Knoll and Fischer, 2011). The rates of environmental change and any potential acidification have not yet been accurately constrained for these events.

    What I take from this is that extinctions are inevitable, but a mass extinction like the Permian extinction is not inevitable if we limit warming to under 2C. Of course the rate of change in temperature today is unprecedented which I realise gives less weight to my optimism.

    1. Rachel

      I didn’t say that we were headed for a repeat of the end-Permian event. There have been lesser marine mass extinctions, typically associated with ocean anoxic events and carbon isotopic excursions. But this one is going to be very fast, and that might be what makes it unusually disruptive even if TCR is at the lower end of estimates.

      1. Ah, ok sure. I did get from the report that the pace of change is quite a worry as it doesn’t give species sufficient time to adapt. It also looks as though coral reef systems are screwed even under low TCR estimates.

  4. My main concern has always been that an accumulating effect would eventually exceed our ability to repair the damage and so,in terms of infrastructure breakdown, result a cascade effect. If we do not avoid that then youngsters who have learned practical skills, in engineering and agriculture, will have an advantage.

    Having said this, I do think we will squeeze by. The human race has always been quite good at that, albeit it causes a lot more suffering than is necessary.

  5. Thanks. You did a great job summarizing that part of the IPCC report, and with your permission I would like to quote part of your summary in an article I’m writing. I’ll even credit you as Rachel Marten with an “e” this time. :>)

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