Controversies in Science/Are humans causing global warming

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(from Controversies in Science)

Are humans causing global warming?

Points For[edit | edit source]

Increase In Global Average Temperature[edit | edit source]

Several studies on species and their effect on global warming has shown 0.6°C increase in the global average temperature and also estimated to increase at a rapid rate. This rapid change is the primary concern for species. [1]

Tree Ring Data Says Humans are Causing Global Warming[edit | edit source]

By measuring tree rings we can estimate temperatures for the past 600 years and show that human pollution is causing the world's temperature to rise. Research has proven that the tree rings expanded, just like a thermometer, based on the temperature through the years and were also affected by the level of CO2 in the environment.[2]

Global Warming Occurring Long Before Industrial Revolution[edit | edit source]

Ever since the human race invented agriculture around 11,000 years ago, concentrations of methane and CO2 have been steadily increasing. This is more so due to the innovations of deforestation and rice irrigation [3].

Human generations are accumulating CO2 at an increasing rate which is causing global warming[edit | edit source]

The past 150 years of CO2 emissions have been analyzed and monitored to project future trends. A generation is defined in 25 year increments which has provided this study with six samples. From these six samples it is noted that CO2 emissions rise over each generation. The cause for concern is the continued increase of CO2 in the seas and in the atmosphere. That being said, CO2 does not decrease as quickly as it rises thus causing implications for an overabundance of CO2 in the future.[4]

New models indicate that humans impact on environment is more drastic than previously thought[edit | edit source]

Current models fail to acknowledge the fact that CO2 concentration is a part of a cyclical model in which it moves through land and the atmosphere. With a new model in place, the effects on the climate are considered even more damaging than previously thought.

The model used in the research, is based on the assumption that CO2 emissions remain at a constant level. If CO2 emissions were to increase, the overall long term effect would be compounded.

In order to accurately predict climate change in the next 100 years we would have to go back and analyze all the data using the model currently used in this research. [5]

As the population increases, so does the surface temperature.[edit | edit source]

In 1996, Hingane compared two industrialized cites with two non industrialized cities. This study lead to a conclusion that the more industrialized cities with the higher population have a higher surface temperature compared to the small non industrialized towns for many reasons. The main reason being that when the population of the more industrialized cities increases, CO2 emissions increase as well. These emissions are then absorbed by the ocean and land, which affects the climate. [6]

N2O have similar characteristics to chlorofluorocarbons (CFC’s)[edit | edit source]

CFC's have been banned because of their contributions to global warming. N2O and CFC’s (both man made chemicals) are stable gases when they are emitted but once they reach the stratosphere they release ozone depleting chemicals. N2O’s release chemicals including: akin and methyl bromide, which is directly linked to ozone depletion. [7]

Global Warming Affects Species.[edit | edit source]

Research indicates that due to changes in habitat, rapid temperature rise, and other stresses, species may be changing their physical characteristics. Each species is becoming less connected, and possibly even extinct. There is a projection that the average global temperature will continue to rise, as it has already risen 0.6 degrees Celsius in the last 100 years; causing continued concerns for species and their ecosystems.[8]

Global Warming is Already Happening[edit | edit source]

Plant growth in size (40%) and amount (2400%) have made a significant increase in the arctic.[9]

Global Warming and the Export of Dissolved Organic Carbon from Boreal Peatland[edit | edit source]

In addition to changes in temperature, global warming also affects water –table levels and discharge from peatlands. Consequently, this affects the delivery of dissolved organic carbon (DOC) to downstream ecosystems where the productivity control is held along with biochemical cycles and reduction of visible and UV radiation. In conclusion, an increase in temperature has many effects because of the regional carbon resources and the ecology of boreal and arctic surface waters. Global warming is due to the reduction of dissolved organic carbon export from peatlands under warm climates. [10]

Global Warming & Human Activity[edit | edit source]

There is a link between carbons released due to human activity and a shift in the global climate. [11]

Global Warming is Affecting the Polar Bears[edit | edit source]

Polar Bears are under a lot of stress due to the prolonged ice-free period which lasts four months. This in turn increases nutritional stress on the polar bear population. This affects Polar Bears in numerous ways such as declining body conditions, lowered reproductive rates, reduced survival of cubs, and cause of collapse when it comes to polar bear maternity dens, which causes the deaths of the occupants[12].

Changes Humans can make to Limit their Carbon Footprint[edit | edit source]

Due to our growing population, individuals can make subtle changes to their lifestyle which will impact the amount of carbon released into the environment in an effort to limit their negative impact.[13]

Points Against[edit | edit source]

Carbon Dioxide and Other Greenhouse Gases have Little Impact in the Warming of the Earth.[edit | edit source]

CO2 is the major gas that contributes in the heating of our planet. Humans add to the CO2 production but the environmental causes are higher compared to the humans. The increase of those gases accelerates the climate rate. [14]

Space Observations of Cold-Cloud Phase Change[edit | edit source]

The increased effects of cloud glaciations due to dust aerosols is causing the greenhouse effect; however, the increased reflectivity of the clouds has proven to be equal on both sides, and therefore the net thermal effect is relatively the same, keeping the system in equilibrium. [15]

Not so Simple!!![edit | edit source]

The argument made by scientists are that global warming is not as simple as the formula where an increase in Co2 leads to an increase in greenhouse effect which leads to an increase in temperature. The problem with this formula is that the concept of global warming is in fact not this simple but instead is a complex system made of 5 subsystems (atmosphere, hydrosphere, ect...) which have their different temperatures as well as multiple factors that compose their own individual climates.[16]

Coral Reef Depletion is NOT caused by Global Warming[edit | edit source]

People have linked the depletion of the Great Barrier Reef to Global Warming. Research done by PANS claims that the Great Barrier Reef is 28-36% extinct due to Global Warming. This statistic is exaggerated due to inaccurate mathematic calculation. Other research shows other causes to depletion of Barrier Reefs.[17]

Hockey Stick Graph is Wrong[edit | edit source]

The data used to construct the hockey stick graph contains many errors that together create an incorrect graph that artificially shows a steep climb in temperature since the industrial revolution.[18]

Is the Decline of Ice on Kilimanjaro Unprecedented in the Holocene?[edit | edit source]

The decline in the amount of ice on Mount Kilimanjaro is not due to global warming but is a feature of the current epoch- The Holocene.[19]

GHG Not Destructive to Thermal Radiation[edit | edit source]

Lindzen argues that global warming is not primarily anthropogenic, and that greenhouse gas is not as detrimental to the Earth’s cooling as previously believed. [20]

Trees Disprove Global Warming[edit | edit source]

Tree rings are often used to measure past climates which has been a focus especially in the last 1000 years. Divergences occur however, when a tree grows at an unusual rate outside of the calibration period. As a result of these divergences, trees are not a reliable source for comparing the climate in recent decades with the climate of historical decades. There are many factors that could have contributed to the divergences outside of climate.[21]

Mount Pinatubo Eruption Caused Climate Change[edit | edit source]

In 1991 a sulfur dioxide cloud from the eruption of Mount Pinatubo was released into the stratosphere. It caused what is believed to be the largest aerosol disturbance of the stratosphere in the twentieth century. Three years after the eruption, the Earth's surface witnessed a climate change of 1.3 degrees. [22]

References[edit | edit source]

  1. Root, T., Price, J., Hall, K., Schneider, S., Rosenzweig, C., & Pounds, A. (2003). Fingerprints of global warming on wild animals and plants. Macmillian Magazines Ltd , 421 (6918), 57-60.
  2. Mann, ME (1998). Global-scale temperature patterns and climate forcing over the past six centuries. Nature (London) (0028-0836), 392 (6678), 779.
  3. Ruddiman, W. (2005). How Did Humans Fist Alter Global Climate?. Scientific American. Retrieved from
  4. Friedlingstein, P., Solomon, S. (2005). Contributions of past and present human generations to committed warming caused by carbon dioxide. Proceedings of the National Academy of Sciences, 102, 10832-10836.
  5. Cox, P. M., Betts, R. A., Jones, C. D., Spall, S. A.,& Totterdell, I. J. (2000). Acceleration of global warming due to carbon-cycle feed backs in a coupled climate model. Nature, 408, 184-187. Retrieved November 1, 2011, from
  6. Khandekar, M., Murty, T., & Chittibabu, P. (2005The Global Warming Debate: A Review of the State of Science. Pure & Applied Geophysics, 162(8/9), 1557-1586. doi:10.1007/s00024-005-2683-x. Retrieved February 14, 2012
  7. Ravishankara, A.R., (2009). Nitrous Oxide (N2O): The Dominant Ozone-Depleting Substance Emitted in the 21st Century. Science, 326, 123 – 125. Retrieved from
  8. Root, T. L., Price, J. T., Hall, K. R., Schneider, S. H., Rosenzweig, Cynthia, Pounds, J. A. (2003). Fingerprints of global warming on wild animals and plants. Nature, 421(6918), 57-61.
  9. Hughes, L (2000). "Biological consequences of global warming: is the signal already apparent?". Trends in ecology & evolution (Amsterdam) (0169-5347)., 15 (2), 56.
  10. Pastor, J., Solin, J., Bridgham, S. D., Updegraff, K., Harth, C., Weishampel, P., & Dewey, B. (2003).).a critique of Global warming and the export of dissolved organic carbon from boreal peatlands.Global warming and the export of dissolved organic carbon from boreal peatlands Oikos, 100(2), 380-386. doi:10.1034/j.1600-0706.2003.11774.x
  11. Alexiadis, A. (2006)Global warming and human activity: A model for studying the potential instability of the carbon dioxide/temperature feedback mechanism,Ecological Modeling. 3(3,4), 243-256. Retrieved November 2, 2010 from
  12. Stirling, I & Derocher,A.(1993). Possible Impacts of Climatic Warming on Polar Bears. Retrieved from
  13. Ghoniem A. F. (2011). Needs, resources and climate change: Clean and efficient conversion technologies. Progress in Energy and Combustion Science,37 (1)15-51.
  14. Khilyuk, L., & Chilingar, G. (2004). Global warming and long term climatic changes: a progress report. environmental geology, 46(6), 970-979. Retrieved on March 8, 2011 from
  15. Choi, Y.-S. (06/2010). "Space observations of cold-cloud phase change". PNAS : Proceedings of the National Academy of Sciences (0027-8424), 107 (25), 11211.DOI: 10.1073/pnas.1006241107
  17. Ridd, Peter V. (11/2007). "A CRITIQUE OF A METHOD TO DETERMINE LONG-TERM DECLINE OF CORAL REEF ECOSYSTEMS". Energy & environment (Essex, England) (0958-305X), 18 (6), 783. DOI: 10.1260/095830507782088578
  18. McIntyre, S., McKitrick R. (2003) Corrections to the Mann et. al.(1998) proxy data base and northern hemispheric average temperature series. Energy & environment 14 (6)
  19. Georg Kaser, Thomas Mölg, Nicolas J. Cullen, Douglas R. Hardy and Michael Winkler (2010). Is the decline of ice on Kilimanjaro unprecedented in the Holocene? Retrieved from:
  20. ZHAO, X. (2011). Is Global Warming Mainly Due to Anthropogenic Greenhouse Gas Emissions? Energy Sources Part A: Recovery, Utilization & Environmental Effects , 33(21), 1985-1992. doi:10.1080/15567030903515013
  21. Loehle, C. (2008). A mathematical analysis of the divergence problem in dendroclimatology
  22. Bluth, J., G., Doiron, D., S., Krueger, J., A., Schnetzler, C., C., & Welter, S., L. (1992). Global tracking from SO2 clouds from the June 1991 Mount Pinatubo eruptions. Geophysical research letters, 19(2), 151-154.