KT: That’s a $64,000 question. In general, under global climate change, it’s suspected that the NAO becomes a little more positive. But in the last two years, it’s become quite negative, and so the speculation is about whether the negative phase is in any way related to the decrease in Arctic sea ice.
Global warming/NAO connection didn’t work. Let’s try explaining the cold as due to a missing ice cube in the Barents Sea.
M-M: Are these current weather events anomalous?
KT: One measure of how anomalous things are is whether you’re breaking records. There have been more record-breaking events than expected. In the U.S., for instance, the number of high temperature events has more than doubled [in the first decade of the 21st century]. What’s happened is that the ratio of record-breaking hot events to cold events is about 2 to 1.
M-M: At what point would you be concerned about the freak weather signaling something truly deleterious about our climate?
KT: I already am. Natural variability is going on all the time and the biggest effects are from the El Niño. Between May 2009 and May 2010, we had quite a strong El Niño. When the mini-global warming from El Niño is added on, we really start to break records when the heat starts coming out of the ocean, as in July of last year. There was record-breaking flooding in China and India and then in August in Pakistan. Last September was the wettest on record in Australia. Then there was record-breaking flooding in Queensland, Australia, from December 2010 into January 2011. Those events were associated with quite high sea surface temperatures in the Indian Ocean and were partly a consequence of the El Niño and the change in ocean circulation. The residual effects of the El Niño meant there was extra evaporation and extra moisture available for the monsoons — first in Asia and subsequently in Australia.
Do these guys ever actually check the historical records before claiming them?
M-M: Have these El Niños become more pronounced due to global warming?
KT: We have records of El Niño going back some 150 years, and there was a change in how it evolved starting somewhere around 1976. Today, the impacts of El Niño due to the floods and droughts around the world are certainly bigger. So while there are floods in South Asia and Australia, there are droughts in Africa and Peru and Equador. During El Niño, it tends to be wetter across the southern U.S. and drier in the north.
Pffftt. That is called the PDO shift, not the CO2 shift.
M-M: So, climate change really manifests itself with more weather extremes?
KT: Because water vapor in the atmosphere acts as a fuel for weather systems, the weather systems can get stronger. We can get heavier rains out of it. The two-day rains last May in Nashville, Tenn., were astounding. As for snow, if it’s a bit warmer but still below freezing, you can actually get more snow, as with some of the East Coast snow storms. Because there’s more moisture in the atmosphere, it gets dumped down in the form of snow instead of rain.
M-M: And you’re saying there’s more moisture in the air because globally the air is warmer?
KT: That’s correct — in particular over the oceans. The main hydrological source of moisture is the oceans. The fact that sea temperatures are half to one degree centigrade above what they were 30 years ago is enough to bolster the snow amounts by at least 10 percent, if not more.
M-M: Are you at all wary of interpreting extreme weather events as evidence for longer-term climate change?
KT: Yes, but it is the main way climate change is expressed.
Warm weather is climate. Cold weather is ignored.
M-M: How effective is comparative paleo-climatology, in other words, the study of ice cores and historical records, in helping your group understand the current climate?
KT: It helps, but the paleo data have large uncertainties and require careful interpretation. There’s an infinite variety in weather, and some of it occurs on relatively long timescales. The thing that is most clear is the increasing temperatures. Along with that, there’s more water vapor in the atmosphere. Beyond that, we can look to sea levels rising, Arctic sea ice and glaciers melting. All this is consistent with this warming. There’s also pretty good evidence that when it rains, it rains harder than it used to especially across the U.S. That’s due to anthropogenic climate change, and that’s only going to get bigger.
M-M: Is the climate definitely changing?
KT: The climate is continuing to change. One way change is manifested is through these extreme events. These are the ones that impact ecosystems and society. But because they are extreme, they are relatively rare and statistics on them are not good, but they are consistent with climate change. Because of that warming, there’s more water vapor in the atmosphere.
No hurricanes for almost three years in the US. Hurricanes and tornadoes on the decline. Lowest ACE in history.
M-M: What’s needed in terms of resources or technology to improve long-term climate models?
KT: Warming has been well verified, but the models have major limitations, and regional climate is not very predictable. So, we need better observations and treatment of them. This includes assimilation of the data and its analysis into global gridded fields. The models also need to be improved.
M-M: What can we expect in the next couple of years?
KT: Because these extreme events lie outside what has been planned for, things like water systems and dikes and dams can be broken, as [seen] with Hurricane Katrina. The rains now are heavier than they used to be, so levees along the Mississippi and in California have also been breached. I expect that we will continue to see things we’ve never seen before.
http://www.miller-mccune.com/environment/crazy-weather-and-climate-do-dots-connect-30059/
“Because of that warming, there’s more water vapor in the atmosphere”
That’s a nice theory, except that global humidity has been falling.
KT: As I was laying on my bed last night I was afraid to look under it because I kept thinking global warming is down there……. at least that’s what I want you to think. You see, by you believing in global warming that’s how I have job security.
Don’t they bother at all with the truth- the Brisbane floods were only the worst since 1974. Nowhere near a record. In fact there have been far fewer floods in Brisbane over the last century than the previous century, and earlier floods have been up to several metres higher.
Also el Nino- that was so the year before last, this year it has been la Nina, the opposite effect. When we have el Nino we have droughts. We know because it has all happened before- genuinely climate, not weather, not responding to the alarmists scenario.
The Brisbane floods this year were mainly due to the fact that they didn’t manage the water levels behind the dam – because they were worried about drought.
Didn’t the dam controller rely on models instead of actually measuring water levels or was it another dam?
They actually let waters build up behind the dam last summer ( i.e Aug!!) because of some law that said water was a valuable resource, even though proper meteorologists were forecasting the likelihood of much wetter weather.
If they had maintained lower levels then, there would have been no flooding at all.
Great theory; now here are the facts after over 30 years of man-made global warming.
Tropical cyclone activity at 33 year low
http://www.coaps.fsu.edu/~maue/tropical/
There has been no trend in global hurricane activity (1965–2008)
Climate Control of the Global Tropical Storm Days (1965–2008), Wang, B., Y. Yang, Q.-H. Ding, H. Murakami, and F. Huang, Geophysical Research Letters, April 6, 2010 (Vol. 37, L07704″
http://www.agu.org/journals/ABS/2010/2010GL042487.shtml
Boreal forest fires may continue decreasing in a warming world.
The weather isn’t getting weirder.
http://onlinelibrary.wiley.com/doi/10.1002/qj.776/full
What people must realise is that these alarmist scientist have families to feed and have nailed their flags to the mast. They cannot now change without losing face. Dr. Judith Curry got out in time and others should pay attention and follow suit before it’s too late for their careers.
Mr (Dr?) Trenberth says that el nino events cause flooding in Australia. He has that backwards. el nino generally causes droughts in Aus. The recent Crisbane floods were part of a la nina.
You’re right! But, he got a lot of things backwards and just plain wrong in his statements. There is no correlation with winter precipitation and temps. As Steve points out, tornadoes and hurricanes aren’t increasing in either quantity or intensity. And there isn’t a way to quantify the flooding, but every year brings some somewhere on the planet.
“Today, the impacts of El Niño due to the floods and droughts around the world are certainly bigger. ”
The word “impacts” is a nebulus word. Is it monetary? Ecological? Deaths? What does it mean? The floods of the Nile were floods but no none would claim they were negative impacts.
Warming causes moisture to be dumped down as snow rather than rain? That is totally absurd and contradictory.