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Global warming is real

Website 1: You can see increasing temperatures all around the globe from now a century and a half ago to now. The Earth's average temperature has risen more than 1 degree Fahrenheit (0.8 degrees Celsius) over the last century, and about twice that in parts of the Arctic. What else can cause the polar ice caps to melt? Models allow scientists to make predictions about the future climate. Basically, models simulate how the atmosphere and oceans absorb energy from the sun and transport it around the globe. ______________________________________________________________________________________________________________________________ Website 2: Atmosphere Carbon Dioxide are higher today than any other time in the last 650,000 years. They are about 35% higher than before the industrial revolution. The concentrations of carbon dioxide and other greenhouse gases in atmospheric samples have been measured continuously since the late 1950s. Since then, carbon dioxide concentrations have increased steadily from about 315 parts per million in the late 1950s to about 385 ppm now, with small spatial variations away from major sources of emissions. Concentrations of carbon dioxide are measured in parts per million, those of methane and nitrous oxide in parts per billion. These are trace constituents of the atmosphere. Together with water vapor, they account for less than 1% of the volume of the atmosphere. And yet they are crucially important for Earth"s climate. ______________________________________________________________________________________________________________________________ Website 3: The temperature keeps rising and lowering at an extreme levels. Sea levels are rising. Natural disasters are happening more often. ______________________________________________________________________________________________________________________________ Website 4: Sea levels are rising up in the last 2,000 years. "The planet is red" in a global map of the change in average surface temperatures, noted Swiss climate scientist Thomas Stocker, co-chair of IPCC Working Group I responsible for this summary at a press conference. "The world is warming." In 2007 the human effect on the climate has grown 40 percent. ______________________________________________________________________________________________________________________________ ______________________________________________________________________________________________________________________________ Websites used- Website 1: http://environment.nationalgeographic.com... Website 2: http://www.skeptic.com... Website 3: http://www.dosomething.org... Website 4: http://www.scientificamerican.com... ______________________________________________________________________________________________________________________________ ______________________________________________________________________________________________________________________________ I am finished and i will hand it over to my opponent.I wish the best of luck.

Global climate models are accurate enough to be relied upon

Models can accurately reproduce past climate changes: Climate models have successfully simulated many aspects of the climate changes observed during the instrumental period. Most notably, models have reporduced the increase in surface air temperatures remarkably well (1-2). Scientists have also found a high degree of similarity between the simulated and observed evolution of global lower stratospheric temperatures during the past 25 years (3). Good agreement between model projections and observations has likewise been reported for decreases in Arctic Ocean ice cover. As one researcher concluded, “The simulated decreasing trend in average sea ice extent for 1970–1999 (–2.5% per decade) is very similar to observations" (4). In addition, model projections are consistent with observations of changes in ocean heat content since 1960 (5). Models have predicted changes in atmospheric temperatures nearly perfectly: In 1988, Dr. James Hansen predicted future atmospheric temperature changes using several different emissions scenarios. His second scenario most closely resembled the observed pattern of carbon dioxide emissions. Models which employed this scenario predicted that we should have seen .33 degrees Celsius of warming between 1988 and 2005. In actuality, we observed .32 degrees of warming, almost exactly what the models predicted (6). Climate models can accurately simulate important feedbacks: Climate models predict that atmospheric water vapor will increase as the surface warms. Observations have independently confirmed these predictions. Satellite measurements indicate that the total atmospheric water content, which is dominated by water vapor in the lower troposphere, has increased at a rate consistent with model predictions (7-8). Interestingly, upper tropospheric water vapor has also increased during the past two decades (9). Climate model simulations indicate that cloud cover changes will most likely amplify greenhouse gas warming. Observations have confirmed that these predictions are also correct. As Dr. Andrew Dessler noted, “The short-term cloud feedback has a magnitude of 0.54 ± 0.74 watts per square meter per kelvin, meaning that it is likely positive...Calculations of short-term cloud feedback in climate models yield a similar feedback” (10). In a few instances, models have been even more accurate than data: Observations themselves are not without error. In a few cases, model simulations have been even more accurate than data. For example, climate models in the 1990s could not reproduce the full extent of the Northern Hemispheric cooling in the 1950s as indicated by observational data. However, a careful analysis later revealed that the data had been distorted by a change in the way ocean temperatures were measured after World War II (11). In another example, satellite measurements in the early 2000s showed essentially no warming in the middle levels of the atmosphere. More direct measurements by balloons and radiosondes likewise showed no warming there. However, a "tropospheric hot spot" had been predicted by all models clear back to the 1970s. This alleged discrepancy was resolved to the satisfaction of most modelers in 2005, when several researchers documented errors in the sets of observations. For example, the observers had not taken proper account of how instruments in the weather balloons heated up when struck by sunlight. Once these errors were accounted for, it was evident that the middle levels of the atmosphere had indeed been warming up (12). Conclusion: As Dr. Michael Mann remarked, “Current climate models do a remarkably good job of reproducing key features of the actual climate...They also closely reproduce past climate changes. We therefore have good reason to take their predictions of possible future changes in climate seriously” (13). References: http://ipcc.ch... http://150.229.66.66/staff/jma/meehl_additivity.pdf http://atmosdyn.yonsei.ac.kr... http://www.cpom.org... http://www.sciencemag.org... http://pubs.giss.nasa.gov... http://geotest.tamu.edu... http://www.cgd.ucar.edu... http://www.dca.iag.usp.br... http://geotest.tamu.edu... http://www.atmos.colostate.edu... http://www.geo.utexas.edu... Mann, Michael E., and Lee R. Kump. Dire Predictions. New York: Pearson Education, 2008. Print.

Global climate models are accurate enough to be relied upon

My opponent's quotes: In the previous round, my opponent presented several quotes from experts who seemed to believe that models are not accurate enough to be relied upon. However, many of these quotes were taken from seriously flawed studies or biased sources. For instance, let’s consider his second quote which came from a scientific paper published by Douglass, Christy, Pearson, and Singer in late 2007. This paper purported to demonstrate that modeled and observed tropical temperature trends disagree to a statistically significant extent. However, other scientists have identified major flaws in this study. As Dr. Ben Santer and his colleagues stated, “The author’s conclusions were based on the application of a flawed statistical test and the use of older observational datasets.” (1) Once these errors were corrected, Dr. Santer found that model simulations matched the observations very closely. Let’s also examine my opponent’s third quote which came from an expert affiliated with the National Center for Policy Analysis. Interestingly, this conservative think tank has received thousands of dollars in funding from ExxonMobil and the Koch Industries. (2-3) As extensive research has shown, the conclusions of a scientific study usually support the interests of the study's financial sponsor. (4-5) Therefore, the quote my opponent provided should not be weighted heavily. Hansen’s projections: My opponent claims that I compared Hansen’s projections to only land temperature data. However, if my opponent had examined my sixth reference, he would realize that this is not the case. In reality, I compared the model projections to the GISS land-ocean temperature index, which includes data from all over the globe. My opponent also alleges that I compared the temperature data to model projections for Hansen’s “C” scenario. However, as I explained very clearly, I actually compared the data to the more realistic “B” scenario. Clearly, I was not "cherry-picking" data, as my opponent alleges. Dessler’s findings: My opponent claims that Dessler’s findings have been refuted by a study conducted by Roy Spencer. However, this is not the case. Spencer’s study was published nearly four years ago, while Dessler’s study was just released six months ago. Moreover, Spencer analyzed only five years of satellite data while Dessler considered an entire decade of observations. Spencer himself has even stated that,"The time scales addressed here are short and not necessarily indicative of climate time scales". Thus, we can be virtually certain that Dessler’s results are much more robust than Spencer’s. Dessler's conclusions are also supported by a variety of studies showing that Lindzen’s IRIS hypothesis is incorrect. (6-8) As Lin et al. stated, “The observations show that the clouds have much higher albedos and moderately larger longwave fluxes than those assumed by Lindzen et al. As a result, decreases in these clouds would cause a significant but weak positive feedback to the climate system, instead of providing a strong negative feedback.” (6) Upper Tropospheric warming: My opponent claims that the troposphere is not warming as rapidly as models predict. He cites two studies to back up this claim, both of which were published over four years ago. Obviously, new satellite and radiosonde datasets have been developed since the publication of these studies. These new datasets show enhanced tropospheric warming due to improvements in our ability to identify and adjust for biases introduced by changes over time in the instruments used to measure temperature. (1) As one study concluded, two newly adjusted radiosonde time series indicate that the upper troposphere is warming at a rate of .2–.3ºC per decade. This is almost exactly what the models have predicted. (9) Other independent observations also indicate that the upper troposphere is warming at a rate consistent with models. For example, one study used measurements of wind shear to estimate temperature trends. This study concluded as follows: “We derive estimates of temperature trends for the upper troposphere to the lower stratosphere since 1970. Over the period of observations, we find a maximum warming trend of 0.65º K per decade near the 200 hPa pressure level, below the tropical tropopause. Warming patterns are consistent with model predictions except for small discrepancies close to the tropopause. The agreement with models increases confidence in current model-based predictions of future climate change.” (10) In summary, the discrepancies that my opponent pointed out were most likely due to inaccuracies in the old observational datasets, not fundamental model errors. This is just another example demonstrating that models can actually be more accurate than data. Response to the Mount Pinatubo eruption: When Mount Pinatubo erupted in 1991, it provided a meaningful opportunity to evaluate how accurately models could predict the climate response to an increase in sulfate aerosols. The models accurately forecasted the subsequent global cooling of about 0.5°C soon after the eruption. Furthermore, the radiative, water vapor and dynamical feedbacks included in the models were verified. (11) Simulations of the planet’s energy imbalance: Global climate models have accurately simulated the planetary energy imbalance. As Dr. James Hansen concluded, “Our climate model...calculates that Earth is now absorbing 0.85 watts per square meter more energy from the Sun than it is emitting to space. This imbalance is confirmed by precise measurements of increasing ocean heat content over the past 10 years.” (12) Conclusion: As the Intergovernmental Panel on Climate Change concluded, “There is considerable confidence that climate models provide credible quantitative estimates of future climate change, particularly at continental scales and above. This confidence comes from the foundation of the models in accepted physical principles and from their ability to reproduce observed features of current climate and past climate changes. Over several decades of development, models have consistently provided a robust and unambiguous picture of significant climate warming in response to increasing greenhouse gases.” (13). References: http://www.realclimate.org... http://www.guardian.co.uk... http://www.greenpeace.org... http://www.bmj.com... http://onlinelibrary.wiley.com... http://journals.ametsoc.org... http://www.atmos-chem-phys-discuss.net... http://journals.ametsoc.org... http://journals.ametsoc.org... http://www.nature.com... http://pubs.giss.nasa.gov... http://pubs.giss.nasa.gov... http://ipcc.ch...

Global Warming is Real.

GLOBAL WARMING IS REAL Atmospheric carbon dioxide concentrations are higher today than at any time in at least the past 650,000 years. They are about 35% higher than before the industrial revolution, and this increase is caused by human activities, primarily the burning of fossil fuels. http://www.skeptic.com...; src="../../../photos/albums/1/4/3238/96287-3238-v3vsm-a.jpg" alt="http://www.skeptic.com...; /> http://www.skeptic.com...; src="../../../photos/albums/1/4/3238/96287-3238-38un8-a.jpg" alt="http://www.skeptic.com...; /> Earth has been in radiative imbalance since at least the 1970s, where less energy leaves the athmosphere than enters it. Most of this extra energy has been absorbed by the oceans. It is very likely that human activities substantially contributed to this increase in ocean heat content. The amount of heat stored in the oceans is one of the most important diagnostics for global warming, because about 90% of the additional heat is stored there. The atmosphere stores only about 2% because of its small heat capacity. The surface (including the continental ice masses) can only absorb heat slowly because it is a poor heat conductor. Thus, heat absorbed by the oceans accounts for almost all of the planet’s radiative imbalance. http://www.realclimate.org...; src="../../../photos/albums/1/4/3238/96287-3238-7g8k4-a.jpg" alt="http://www.realclimate.org...; /> Signs that the Earth is warming are recorded all over the globe. The easiest way to see increasing temperatures is through the thermometer records kept over the past century and a half. Around the world, the Earth's average temperature has risen more than 1 degree Fahrenheit (0.8 degrees Celsius) over the last century, and about twice that in parts of the Arctic. "The planet is red" in a global map of the change in average surface temperatures, noted Swiss climate scientist Thomas Stocker, co-chair of IPCC Working Group I responsible for this summary at a press conference. "The world is warming." http://data.giss.nasa.gov...; src="../../../photos/albums/1/4/3238/96287-3238-kw63s-a.jpg" alt="http://data.giss.nasa.gov...; /> The Earth's average surface temperature rose by 0.74±0.18 °C over the period 1906–2005. The rate of warming over the last half of that period was almost double that for the period as a whole (0.13±0.03 °C per decade, versus 0.07±0.02 °C per decade). The urban heat island effect is very small, estimated to account for less than 0.002 °C of warming per decade since 1900. Temperatures in the lower troposphere have increased between 0.13 and 0.22 °C (0.22 and 0.4 °F) per decade since 1979, according to satellite temperature measurements. Climate proxies show the temperature to have been relatively stable over the one or two thousand years before 1850, with regionally varying fluctuations such as the Medieval Warm Period and the Little Ice Age. The climate system can respond to changes in external forcings. External forcings can "push" the climate in the direction of warming or cooling. Examples of external forcings include changes in atmospheric composition (e.g., increased concentrations of greenhouse gases), solar luminosity, volcanic eruptions, and variations in Earth's orbit around the Sun. Orbital cycles vary slowly over tens of thousands of years and at present are in an overall cooling trend which would be expected to lead towards an ice age, but the 20th century instrumental temperature record shows a sudden rise in global temperatures. For a direct look at the atmosphere of the past, scientists drill cores through the Earth's polar ice sheets. Tiny bubbles trapped in the gas are actually pieces of the Earth's past atmosphere, frozen in time. That's how we know that the concentrations of greenhouse gases since the industrial revolution are higher than they've been for hundreds of thousands of years. But if Global Warming is real, then why it is cold in US now? First of all US is not whole Earth, second of all may be because it is winter in northern pole. December 2013 was an unusually warm month even though it was colder in the U.S. In past December, North America was colder than the average over the past decade. But Europe and Russia were much hotter than average. India was cooler than average. Australia was warmer than average. Global Temprature is the average temprature of globe, and sorry US is not globe (and who cares about US). http://www.youtube.com... [1] - http://on.natgeo.com/1bNQQJe [2] - http://bit.ly/1acL5Jh [3] - http://wapo.st/1idDRX8 [4] - http://bit.ly/1eiNzEA [5] - http://bit.ly/1bNR6rL [6] - http://bit.ly/19YXkZi [7] - http://1.usa.gov/1eEHLWB [8] - http://bit.ly/1cyoK8s [9] - http://bit.ly/1cyoLJA