Don Wuebbles, University of Illinois
Is the extreme weather of recent years a consequence of climate change? Climate scientist, IPCC lead author and 2007 Nobel Peace Prize-winner Don Wuebbles explains " alt="Monsoon clouds" />to Chris Smith why he thinks this is a taste of what is to come...
Don - The climate is changing worldwide, climate being the long term variations in weather of course, but it’s much more than that. The fact that that change's occurring because of human activity's becoming clearer and clearer over time. We now are beginning to even talk about that dangerous climate change isn't just going to happen in the future. It’s happening now.
Chris - Just summarise for us what the big changes are. What are we seeing and where?
Don - So, we’re seeing overall long term changes in temperature. We’re seeing relatively small changes overall in precipitation. Some places getting dryer, some places getting wetter, but it’s much more than that. It’s this concern about severe weather. We’re seeing much more concern about heat waves, less cold waves overall. We’re also seeing more precipitation coming as much larger events than in the past.
Chris - What do we think the drivers of this are?
Don - The analysis are very clear, that you cannot explain these long term changes we’re seeing as being due to natural causes. The only thing that really is able to explain the observed changes is the fact that because of our burning of fossil fuels, other human induced changes in our planet that we’re increasing the amount of carbon dioxide, the amount of methane, the amount of some other key gases. And those gases so happen are very important to life on Earth in the first place because without those gases, we wouldn't have life here as we know it. This would be a frozen planet. So, having those greenhouse gases is really important. The problem is, because of human activities, we’re increasing the amount of those greenhouse gases substantially. The amount of carbon dioxide for example has increased from about 280 parts per million to over 400 parts per million and it continuously increase and that's driving changes. We haven’t seen levels of carbon dioxide in the Earth’s atmosphere of that size for over 2 million years.
Chris - Do we know what the weather was like 2 million years ago when it was that high?
Don - We don't totally know what the weather was, but we do know that it was a much, much warmer climate on this planet at that time than it is now. Places like Antarctica and Greenland were without ice. Much higher sea levels, we may not be worried about what's going to happen in the next several thousand years, but we certainly should be concerned about what's going to happen over the century when these changes in climate are going to be affecting our children, our grandchildren.
Chris - Obviously, 2 million years ago, there were early pre-humans around, but they certainly weren’t emitting CO2 the way that we modern humans are now. So, where did the CO2 that was in the atmosphere and at high level then come from?
Don - Those high levels of carbon dioxide actually came from outgassing from very large volcanoes. Current volcanic eruptions have very small effects in the amount of CO2 in the atmosphere, much, much less than human amount and really, do not contribute to the increase that we’re seeing now.
Chris - What about the severe weather manifestations that we’re now seeing potentially linked to this? Why do we get more severe weather when the CO2 in the atmosphere rises?
Don - Some aspects of it, we understand pretty well. We know for example as the temperature is increasing, that a warmer atmosphere can hold more water vapour. And so, that additional water vapour is then available for precipitation. In addition, there's just more overall energy in the entire Earth’s system because of this increases in these gases. It’s just overall trapping more energy into the Earth. So, we expect things like more precipitation coming as larger events. But also, analyses are tending to show that some very large events like hurricanes are likely to be more intense in the future. Right now, we can't say much about the number, but the intensity is likely to be larger.
Chris - What about time scale? When should I consider moving further from the coast?
Don - Well, the big concern of the coast particularly are going to be the increase in sea level and storm surge. The projections over this century are something like 20 to 80 centimetres by IBCC. I think in the National Climate Assessment, we were a little bit more generous and said it could be as much as a meter. None of that is going to happen soon, but we are seeing an acceleration in the rate of sea level rise. I think you clearly have several decades available for you to still live near the coast, but after the next few decades or so, you may get concerned.
Like there was ever a time in the history of the Earth that the climate wasn't changing? MeatAndPotatoes, Mon, 9th Jun 2014
It's about rate of change and recklessly messing with something which is gernerally stable and which we rely upon ramaining stable. David Cooper, Mon, 9th Jun 2014
It is very difficult to track changing storm patterns. There is a huge recording and detection bias, and just a couple of decades, most weak tornadoes were either not detected, or not recorded. Rare events such as Cat-5 Hurricane landfalls are not common enough to calculate changes in probability.
There's a serious problem of observation bias here. How do you measure the severity of a storm?
Sure it is. It has to, considering the new man made amount of energy that is getting stored inside Earths atmospheric envelope, relative the 'empty space' outside earths exosphere. How it will act regionally/locally is another thing, and I suspect very hard to predict. I mean, it's no different from weather predictions today, only more volatile as the energy goes up.
Storm amplification is a direct effect of solar geoengineering with coal fly ash particles. tkadm30, Thu, 31st Mar 2016
Do you have anyevidence that storms are getting worse?
Another wild card variable is connected to how the media deals with climate change. For example, if there is one airline crash, this can get so much coverage and expert analysis, some people will begin to think airline crashes have become a common event, worse than ever. All the planes are about to fall from then sky.
Fault lines don't cause storms.
In America, opinions about climate change, formerly called global warming, is divided down political lines. Conservatives tend to use the test proven trends of the past to judge the present, while liberals tend to ignore the past and/or revise the past, and then follow the narrower time scale of the latest fad. One might be able to infer how the divide, down these difference in political instincts, reflect the nature of data collection.
Why would I want to conduct a biased study? alancalverd, Sat, 2nd Apr 2016
It's certainly good enough for local market gardeners who use diesel generators to make...CO2! They sell the electricity as a useless byproduct and pipe the gas into their greenhouses to accelerate plant growth. The glasshouse atmosphere is actually toxic to humans. alancalverd, Sat, 2nd Apr 2016
In my opinion(s) - these are my opinions, because I'm not qualified to state them as fact, but I as understand these specific opinions are in agreement with scientific facts presented as my opinions.
I spent more than 10 years in the field of hydrology and I have already told you that water vapour drives the temperature. But hey you know best. jeffreyH, Thu, 7th Apr 2016
Craig you have to ask yourself what is about atmospheric water vapour that could decrease the efficiency of natural carbon sinks? If you can answer that question you will reach enlightenment grasshopper. jeffreyH, Thu, 7th Apr 2016
http://m.phys.org/news/2014-07-vapor-global-amplifier.html jeffreyH, Thu, 7th Apr 2016
Yes it exactly is. Climate has been changing. henrycalvin, Fri, 8th Apr 2016
Agreed, but the number and severity of storms, at least according to NOAA, has decreased.
The current climate change is connected to an El Nino affect, which is a large pocket of warm water in the oceans near the equator. A La Nina is based on cooler water and can also impact climate.
Pretty much just because I was exploring the site I found this:
You are obsessed with carbon dioxide. Do you have OCD by any chance. So you read some books. Big deal. I bet those authors were never anywhere near live datasets. Climate change sells books because it is trendy. No vested interest there then. jeffreyH, Fri, 8th Apr 2016
The reason you have issues in public forums is three fold. Firstly your arrogance. Secondly your resort to insults. Thirdly your inability to engage in a reasonable debate and an unwillingness to consider other viewpoints. jeffreyH, Sat, 9th Apr 2016
For those with more open minds here is a research paper on the role played by water vapour on the climate. It is not as expected. Like many other phenomena, the climatic system can be counter intuitive.
Since a computer model has to be predictive it cannot simply play back raw data. It has to base a simulation on analysis of the instrumentation data. jeffreyH, Sun, 10th Apr 2016