Consequences

The aim of this section is to try and give you a picture of how the world will change through the effects of global warming. There are global consequences from the changing weather patterns, and other associated impacts. What will these mean to you and me? I focus right in on changes we can expect to see in my home town of Reading to help illustrate what climate change will be like. From this you can hopefully get a feel for how much things will change in other parts of the world. Notice that it will make a big difference to the future if we cut down on our emissions now!

Global climate change

Special Report on Emission Scenarios (SRES) - The greatest source of uncertainty for anyone trying to predict how the climate will change is us. How will we behave in the future? Will we take the issue seriously and rapidly cut our emissions of greenhouse gases? Or will it be business as usual? There are a number of Emission Scenarios, which have been modelled to try and understand this.

Global temperature change - Atmospheric scientists use the emission scenarios to predict how much greenhouse gas concentrations will increase in the atmosphere. They can then run Global Climate Models to predict how the temperatures will change in the future, alongside changes in other aspects of the weather like rainfall. Even medium emission scenarios predict increases in average global temperatures by 3ºC, by the end of the century.

Map of the southern two-thirds of the British Isles showing position of Reading

What does that mean for me?

I think it is too difficult to grasp the implications of changes to global changes in average temperatures that we have looked at so far. They are too abstract. Fortunately I can use the new UK climate projections to give me some more local data...

I live in Reading, a town of about 230,000 people, which is situated at the confluence of the River Thames and the River Kennet...approximately 40 miles east of London. I am going to choose my home town to paint a picture of climate change. [i] The thought processes that I need to go through will apply to you as well so hopefully it will help you to picture how change will effect where you live.

Which emission scenario should I use?

Looking at the latest Emissions Targets the future seems to be very uncertain with respect to which emission scenario should I use. I hope that things will change, and that I will need to revising this section next year with a more optimistic picture. At the moment however, we have no international agreements that would stop us from even going above the highest (A1FI) scenario. We also have political rhetoric that tries to commit us to limit us below the lowest (B1) scenario.

All I can guess is that we will end up somewhere in between but I do not know where. I will therefore try and make projections for the highest and lowest scenarios and try and understand the range of possible futures.

Climate change in Reading, SE England

I am going to focus right in to start with, to explore how temperatures are expected to change in my home town: in the 2050s (which I might live to see if I'm lucky), and the 2080s (which my children's generation are likely to live to see). Hopefully this will give us an idea of the range of possible temperatures and the level of confidence behind the changes. There is a lot of information to digest, even to understand temperature changes in a single month. I am going to look at two examples, simply because I find them personally interesting: Spring is my favourite time of the year and it starts for me in March; the other month is August, which is the time of summer holidays, and hence I have memories of playing outside as a kid.

Temperature changes in March - This is an in-depth look at how the UK climate projections (2009) can be used to understand how climate change will effect temperatures, in Reading, in the month of March. I discuss probability in terms of dice rolling, and introduce you to some real temperature data from the University of Reading Atmospheric Observatory, to help visualise what day-to-day temperatures might be like. It seems likely that, even by the 2050s, and even under lower emission scenarios, we will see March temperatures that are more like the averages that we are used to for April in Reading.

Temperature changes in August - Even by 2050 we could experience heat waves, with hottest day temperatures that reach 40ºC in the shade. By the 2080s there is a big difference in the temperatures that we are likely to see by following the high, rather than the low scenario. It looks like it could get uncomfortably hot compared to what we've been used to.

Seasonal changes in 2050 - There is a significant amount of difference expected between the individual seasons, which you cannot understand from the crude estimates of change to average annual temperature. In Reading, we will see summer temperatures increasing more relative to the rest of the year, although it will be milder in all seasons. It looks like winter will be wetter and summer will be drier: there is more uncertainty about how rainfall will change for spring and autumn.

Consequences for Reading

I am still working on the following sections ... please bear with me as I build up the content and check references.

On the face of it, if we ignore the summer, the climate changes that I have presented for Reading look quite nice for the rest of the year. The warmer temperatures suggest that we will be more likely to experience milder, shorter winters; and that we can expect an earlier onset for spring. However, it will also be pleasant for a variety of plants, insects and animals that are not used to surviving in this part of the world, and they in tern may out-compete some of our native species. We are already seeing change in ecosystems. This is likely to continue, and unfortunately the changes in climate are so rapid [i] that we will probably see an increase in pests, this could effect agriculture and possibly effect us directly if there are diseases involved (e.g. mosquitoes carrying malaria).

The winters do look like they are going to get wetter. It seems logical that this will mean more flood events in the future and, depending on how the rainfall patterns change, these events could be more extreme.

Map of average summer temperature change in the 2050s, at the 50% probability level, under the High emission scenario

The hotter summers could be a big problem.

Heat waves, with temperatures over 40ºC in the shade, are hard enough for me if I am on a holiday in the Mediterranean. Reading - in the bottom of the Thames valley - will be very uncomfortable. It is worth noting that 10,000 people died across northern Europe as a result of the heat wave in 2003.
The summers are also expected to be dry, which could have consequences as soils dry out a lot more than we have been used to. This could effect buildings through subsidence, and could effect agriculture. It may also result in droughts as it reduces the effectiveness of the following winter's rainfall.

...and beyond

It is fair to point out that Reading isn't the centre of the Universe! And don't live in isolation. Climate change effects in other parts of the world will be different, and may be more or less extreme. You can see from the adjacent map, of summer temperatures change in the 2050s, high scenario, one example of how climate change is expected to vary across just the UK (you can find more pre-prepared maps like this on the UK Climate Projections 2009 website). You can see that Reading can expect to get relatively warmer than other parts of the country.

Global consequences - To help us understand how climate change will vary across the world, the Met Office have created a map showing the relative change in temperature across the globe. It is notable that other parts of the world are expected to see much bigger changes than Reading. This map also identifies some of the key consequences that individual regions may be expected to have to deal with. These are listed further with links to the IPCC impacts report.

You can see that some places will have to deal with some big challenges. These could effect where people can live, work and grow crops; which in tern will have consequences for global trade.

I am mindful that in the UK we don't manufacture much any more, what are we going to do if environmental problems hit the far east, and we cannot buy cheap clothes and electrical goods (etc)? Will this lead to bigger wobbles in the global economy than we experienced with the banking collapse?
We are also used to a wide variety of exciting foods from around the world. But more importantly, how much do we rely on imported food...will we be able to be self-sufficient in the future?
Finally, it is worth considering that other parts look like they will become very difficult to survive in. There are very likely to be environmental refugees, who may well look to move to the UK as a relatively safe place to be. Can we cope with that influx, whilst trying to balance the resource problems our current population will have to deal with? And it is going to be a hard moral argument turning people away, when you consider our current / historic emissions.

Final points to consider

By the end of the century, if we have followed the lowest emissions scenario, changes to our climate will hopefully be stabilising. I expect to see the start of these changes to weather patterns in my lifetime. They will continue to change and become more extreme for a long time after the year 2100.

If we have followed anything like the high emissions scenario, changes to our climate will be accelerating. The consequences of even the change by the end of the century will make parts of the world very difficult to live in, and will have serious impacts on the rest of the world. Surely this future cannot be allowed to happen.

It is important to understand that there is a long delay before we feel the effects of climate change. It will take decades before the effects of today's increases in greenhouse gases are felt. This makes it so very important that emissions are cut soon, to reduce the amount of change in the future.

There is no getting away from the fact that we will need to adapt to a changing world though. And this will have to happen on top of the pressures on resources and population growth. We are going to have to show a lot of maturity as the human race: we are going to have to work together and help each other. And we must remain sober about this - panic and fighting really wont help.