Friday, September 09, 2016
Warmer, wetter climate would impair California grasslands, 17-year experiment finds
The Greenies love this claim. It overturns just about everything we know about plant growth. There have been any number of experiments showing that CO2 makes plants grow bigger and we know why. And greenhouse owners routinely add CO2 to their greenhouses to improve growth of their crops. So what happened on the occasion below? Apparently the soil in the area was phosphorous deficient and that stopped the plants from taking advantage of the other growth factors. See here
Grassland at Stanford University's Jasper Ridge Biological Preserve. An examination of 17 years of experimental data from the preserve is helping scientists from Rice University, Stanford and the Carnegie Institution for Science better …more
Results from one of the longest-running and most extensive experiments to examine how climate change will affect agricultural productivity show that California grasslands will become less productive if the temperature or precipitation increases substantially above average conditions from the past 40 years.
That's one conclusion from a new study in this week's Early Edition of the Proceedings of the National Academy of Sciences by researchers from Rice University, Stanford University and the Carnegie Institution for Science. The research team analyzed data from the Jasper Ridge Global Change Experiment, which has run continuously since 1998. The experiment simulates the effect of warmer temperatures, increased atmospheric carbon dioxide, increased nitrogen pollution and increased rainfall on a 1.8-acre tract at Stanford's Jasper Ridge Biological Preserve.
"There's been some hope that changing climate conditions would lead to increased productivity of grasses and other plants that draw down carbon dioxide from the atmosphere," said study lead author Kai Zhu, a global ecologist and data scientist at Rice "In northern California, it was hypothesized that net grassland productivity might increase under the warmer, wetter conditions that are predicted by most long-term climate models. Our evidence disproves that idea."
The Jasper Ridge experiment involves 136 test plots where scientists can study how grass will grow under conditions that are predicted to occur later this century due to climate change. The experiment allows scientists to test four variables: higher temperatures, increased precipitation, increased atmospheric CO2 levels and increased nitrogen levels. The plots are configured in such a way that scientists can test each of the variables independently and in combination.
"Global change is quite complicated," said Zhu, who spent almost two years analyzing Jasper Ridge data during a postdoctoral fellowship at Stanford and the Carnegie Institution for Science from 2014 to 2016. "It does not just mean change in temperature. There are also changes in rainfall, atmospheric CO2, nitrogen and many other things. If we want to get a comprehensive understanding of everything, it is important to have experiments like Jasper Ridge, which manipulate more than one variable, both singly and in combination."
One clear finding from the data is that increased levels of CO2 did not increase grass production. Instead, the amount of grass grown at sites with elevated CO2 remained flat, even at CO2 levels almost twice the present atmospheric concentration.
"The nonresponse to CO2 is as important as any of our other findings," Zhu said. "That finding may surprise people because a lot have said that if you have more CO2 in the atmosphere, you'll get better growth because CO2 is a resource for plants. That's a popular hypothesis."
By examining data from all the test plots, including those where CO2 increased in conjunction with higher temperature, rainfall and nitrogen levels, and incorporating more than 40 years of climate records from the Jasper Ridge site, Zhu was able to deduce the optimal temperature and moisture levels for production under all conditions. His analysis showed that average conditions from the past 40 years are near optimal for grass production, and any significant deviation toward warmer or wetter conditions will cause the land to be less productive.
"Experiments like Jasper Ridge are designed to examine the interactive and unexpected effects that are likely to arise from global environmental change," said study co-author Chris Field, the founding director of the Carnegie Institution's Department of Global Ecology and the Melvin and Joan Lane Professor for Interdisciplinary Environmental Studies at Stanford University. "The nonlinear, interactive effects of temperature and precipitation on grassland primary production revealed by this analysis highlight the value of this experimental approach and suggest that it could be useful in studying how global change will affect other types of ecosystems."
Warming improves tree growth
Using dendrochrononlogy, the researchers looked at climate change since 1760, over which time there has been some warming. There may also have been some local warming at times
Word of mouth from nomadic herders led Lucas Silva into Tibetan forests and grasslands. What his team found was startling: Rapid forest growth in tune with what scientists had been expecting from climatic changes triggered by rising levels of carbon dioxide.
Actual scientific findings to date, however, had been turning up declining growths in many forests in the face of climatic changes. Such had also been the case for Silva, who joined the UO's Environmental Studies Program and Department of Geography in August.
On the eastern Tibetan Plateau -- in an area where it was thought that "climatically induced ecological thresholds had not yet been crossed" -- Silva's team found that the increasing availability of soil nutrients and water from thawing permafrost is stimulating the chemistry of the wood in a species of fir trees.
"Our results confirmed the reports of local herders and showed a recent increase in tree growth that has been unprecedented since the year 1760," Silva said. "These result demonstrate that under a specific set of conditions, forests can respond positively to human-induced changes in climate."
The findings were published Aug. 31 in Science Advances, an online, open-access publication of the American Association for the Advancement of Science.
Nomads had reported their observations to study co-author Geng Sun of China's Chengdu Institute of Biology in Sichuan, China. The research team traveled to the region in eastern Tibet where they found old-growth forests, smaller patches of trees and trees isolated on the perimeter of the forests.
"We wanted to take a long term view of changes in tree growth across this gradient," Silva said. "To do so, we combined tree-ring measurements with laboratory analyses to look for changes in growth as well as chemical signals of climatic change."
Those techniques provided a window on the history of the area's tree growth. Dramatic increases in growth have coincided with pulses of tree establishment just outside of the forest range but apparently not yet on a broader regional scale, he said. Growth was rapid between the 1930s and 1960s, but even more accelerated in the last three decades.
CO2-Enrichment Boosts the Growth and Water Use Efficiency of Two Tomato Cultivars
Paper Reviewed: Pazzagli, P.T., Weiner, J. and Liu, F. 2016. Effects of CO2 elevation and irrigation regimes on leaf gas exchange, plant water relations, and water use efficiency of two tomato cultivars. Agricultural Water Management 169: 26-33.
Model projections suggest that mid-latitude regions could experience a higher frequency of seasonal drought as a result of CO2-induced global warming. Therefore, in the words of Pazzagli et al. (2016), "an understanding of plant responses to rising CO2 concentration and limited water availability is necessary for maximizing crop yield and quality under future climate scenarios."
And to help move our understanding forward in this regard, the team of three researchers from Denmark set out to investigate "the independent and combined effects of CO2 enrichment and reduced irrigation on two tomato cultivars with potentially different responses to drought and heat stress."
To accomplish their objective, Pazzagli et al. grew two tomato (Solanum lycopersicum) cultivars -- one potentially drought tolerant (ST 22) and one thought to be heat tolerant (ST 52) -- in a controlled greenhouse environment from March to June 2014 at the experimental farm of the University of Copenhagen located in Taastrup, Denmark.
Therein, the plants were subjected to three different irrigation regimes (full irrigation, deficit irrigation and partial root-zone drying) and two atmospheric CO2 concentrations (380 and 590 ppm). And what did their study reveal?
Statistical analyses indicated there was a significant CO2 effect on both cultivars for net photosynthetic rate, intrinsic water use efficiency (WUEi, photosynthetic rate/stomatal conductance), plant water use efficiency (WUEp, aboveground biomass/plant water use), root water potential, stem dry weight, leaf dry weight, total dry weight (see figure below) and flower number.
More specifically, the photosynthetic rate was 30% higher in plants grown at 590 ppm compared to those grown 380 ppm, total plant dry weight averaged 13.5% higher (18% for ST 52 and 9% for ST 22) and WUEp increased by 25% in ST22 and 13% in ST 52.
In summing up their findings, Pazzagli et al. write that "despite large differences between the cultivars, both of them showed significant improvements in plant water use efficiency under both reduced irrigation and CO2 enrichment, as well as under the combination of the two treatments." In the future, therefore, these two tomato cultivars should benefit from Earth's rising atmospheric CO2 concentration.
Sorry Alarmists, Even Joe Romm Confirms The Pause
Paul Homewood compares present temperatures with those of the previous El Nino in 1998
Joe Romm continues to make an idiot of himself. He uses this graph from UAH to show that even satellites confirm his apocalyptic version of events.
He cherry picks the latest 12 month average, which just so happens to be a miniscule 0.074C higher than at the same stage in 1998. He forgets to tell you though that the current El Nino has been much longer lasting than 1998’s, and consequently temperatures in late 2015 were already comparatively elevated.
He also forgets to tell you that August 2016 is 0.07C cooler than the same month in 1998, or that the last five months have also been cooler this year.
In reality, these differences are no more than weather, and have no significance either way.
He then goes on to label Roy Spencer and John Christy as “deniers”, which is one of the most ludicrous epithets I have ever come across, and just shows how politicised climate science has become.
Romm then goes on to mention that there is another satellite dataset, RSS, which somehow disproves the “deniers’” UAH. Unfortunately for the discredited Romm, the RSS data show exactly the same as UAH’s – the current 12-month average is 0.081 higher than in 1998, but again we find no statistically warming since 1998.
Romm’s only answer to this is to say that there has been warming since 1979:
You will no doubt be shocked, shocked to learn that the satellite data has, in fact, confirmed global warming for a long time. Indeed Dr. Roy Spencer and Dr. John Christy of the University of Alabama at Huntsville (UAH) reported earlier this year that the satellite data shows a “Global climate trend since Nov. 16, 1978 [of] +0.12 C [0.22F] per decade.” And Spencer and Christy are both leading deniers themselves!
Please Joe, do keep up. We all accept that there was warming between 1979 and 1998, which coincided with the PDO switch and the movement of the AMO from its coldest state to its warmest.
It is what has happened since that matters. You know, that thing called the “Pause”, that even the UK Met Office, in July 2013, accepted was real, prior, of course, to the latest super El Nino. Indeed, it was so real, they even wrote a paper about it.
But even if we assume that the rise in temperature since 1998 is part of an underlying change, then so what?
A change of 0.07C over 18 years equates to 0.4C/century. This is way below anything forecast by the IPCC, Joe Romm or any of his well rewarded cohorts, as John Christy points out:
Clinton says Hurricane Hermine was caused by climate change as hurricane drought persists
In an apparent effort to entice Bernie Sanders’ supporters, #Hillary Clinton blamed #Climate Change for Hurricane Hermine, the first hurricane to hit Florida since 2005. At a rally yesterday in Tampa, Florida, Clinton warned that more storms like Hermine were on the horizon despite all indicators pointing in the opposite direction. For those wondering if Clinton would be President #Obama’s third term, putting the climate above the stalled economy is further proof of her priorities.
At the rally, Clinton railed: “Another threat to our country is climate change. 2015 was the hottest year on record, and the science is clear. It’s real. It’s wreaking havoc on communities across America. Last week’s hurricane was another reminder of the devastation that extreme weather can cause, and I send my thoughts and prayers to everyone affected by Hermine.”
No, 2015 wasn’t the hottest year ever
First, 2015 was a warm year because of a strong, naturally occurring El Niño, which elevated temperatures worldwide. It was also not the hottest year on record because the 1930s is still the reigning champ for hottest years since recordkeeping began in the mid-1800s. Since 2000, there has been no statistical warming as acknowledged by the United Nation’s Intergovernmental Panel on Climate Change’s (IPCC) last assessment report, numerous journal articles, and 37 years of satellite temperature records.
Climate experts have noted there has also been no increase in extreme weather events, which include long-term droughts, heavy floods, accelerated sea level rise, more tornadoes, and specifically, hurricanes. In fact, Hermine didn’t break the 11-year hurricane drought in the United States. No major hurricane—category 3 or higher—has made landfall since Hurricane Katrina in 2005. And the first to strike Florida was Hurricane Wilma in October 2005, which devolved into a category 2 after it made landfall.
Hermine, which peaked briefly as a category 1 hurricane before reaching land near St. Marks, Florida, quickly devolved into a tropical depression as the storm flitted across Georgia and into the Atlantic Ocean. All the computer models projected a long-lasting, devastating storm over the busy Labor Day weekend up and down the East Coast. These are the same computer models predicting our climate in 75 years.
Labor Day weekend a bust
Because Hermine was such a rare happenstance after enjoying over a decade without a hurricane hitting Florida, the media covered it like it was an ‘unnatural’ event. Couple that with the pessimistic (and wrong) forecasts, and many people abandoned their Labor Day weekend getaways. Millions stayed at home and coastal hotels stayed largely vacant. But major hurricanes should be occurring much more often even in a non-warming world. The warm ocean water is their fuel, but this drought has been long-running and persistent.
Hillary’s fundraising gambit
More troubling, while Hermine was forecasted to impact Long Island and New York’s long expanse of coastline, Clinton was busily fundraising in the Hamptons, which was directly in Hermine’s path. But with hundreds of millions (of dollars) at stake, even Clinton gambled it wouldn’t be a soaker. She also unveiled her new jet, which she took to Tampa rail for ‘gun control’ and ‘climate change.'
If Clinton was truly concerned about the climate, she would not have unveiled a new charter jet (a Boeing 737) before heading to Tampa. Instead, she should have flown to Louisiana to bring much-needed attention the flood victims. But it’s not a battleground state so why should Clinton, as Louisiana's The Advocate noted, bother to visit their flood-ravaged state? Whether it’s talking points or actual beliefs, the facts are rarely on Hillary’s side.
Northeast US Used To Be In Drought Most Of The Time
People in the Northeastern US have gotten used to wet weather, but from 1910 to 1979 the Northeast was in drought most of the time. Most likely due to your SUV.
Climate at a Glance | National Centers for Environmental Information (NCEI)
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Posted by JR at 12:27 AM