In the past, Earth's climate experienced slow changes due to natural causes not related to human activity such as variations in solar radiation or large volcanic eruptions. Following the Industrial Revolution, humans began releasing large quantities of greenhouse gases and particulate matter into the atmosphere, resulting in rapid, unnatural climate changes that are not yet fully appreciated, or that will impact how organisms experience continued life on Earth. Human induced climate change will produce both negative and positive results.
Scientific Tools for Monitoring Climate Change
The science is available through the use of advanced instruments, decades of data collection and carefully developed scientific methodologies to interpret the data. Scientists closely monitor natural and human activities that impact climate with satellites and surface instruments. For example, NASA satellites record data from aerosols, atmospheric gases, radiation, and ocean surface temperatures. Scientists have been collecting data for decades, aiding in understanding the forces that contribute to climate change. Because the Earth’s climate changes on its own all the time, scientists need to observe data over a span of years to reliably assert that humans are responsible for some of those changes.
Scientific Data Collection for Studying Climate Change
Data collected for analyzing climate change focuses on four main assessments: drivers of climate change, changes observed in the climate system, understanding cause and effect relationships, and projecting future changes. As the IPCC (Intergovernmental Panel on Climate Change) assessment of 2007 points out, growth rates for concentrations of carbon dioxide have been faster in the last 10 years than any other ten year period since consistent atmospheric monitoring began. The IPCC also points out that some greenhouse gases have no natural source.
Two patterns provide further evidence of human influence. Greater warming is occurring over land than in the oceans and greater warming is occurring at the surface of the sea rather than in the deeper layers, patterns consistent with greenhouse gas induced warming. Secondly, the troposphere has warmed while the stratosphere has cooled. If solar changes were responsible, the warming would occur in both layers.
Recently, two Swiss climate modelers employed a new method called “attribution” for understanding the physical causes of climate change. The scientists used existing data, collected over a period of years, and ran the model many times to test the outcome. The findings were similar to those of other climate change studies. By using existing data, the researchers developed a new method of interpreting the data, providing an alternative line of evidence that greenhouse gases, and carbon dioxide in particular, cause global warming.
The Uncertain Future
While most scientists agree that life on Earth will inevitably change due to human induced warming, the type of impact is not yet clear. For example, Stanford agricultural scientist David Lobell points out that poor people who farm their own land could actually benefit in the short term due to climate induced food shortages with subsequent higher market prices. However, a much larger number of urban poor, and those who do not own land, are likely to be negatively impacted by higher food prices. The impact on the environment is not yet clear either. For example, the IPCC pointed out that current estimates show that sea levels are expected to rise approximately 30 to 40 centimeters during the 21st century. Possible consequences are not yet know, and little data is yet available.
In spite of some of the uncertainties as to the consequences of climate change, it is reasonable to conclude with available evidence that human activity is in fact having an impact on Earth’s climate. For better or worse, humans have constructed a global civilization that is currently dependent on many activities that result in climate change. Drastic, immediate change would likely be just as detrimental to human life as simply doing nothing over the long-term. We can realistically change some immediate habits to reduce global warming causing activities, such as simply turning off a light not in use, or driving more sensibly. At the same time, we should be planning for gradual long-term changes in how we use Earth for our benefit.
Sources:
“Is Current Warming Natural,” NASA Earth Observatory.
“Global Warming May Hurt Some Poor Populations, Benefit Others,” Science Daily, February 20, 2010.
Further Reading:
Causes of Global Climate Change Beyond Carbon Dioxide
Matthew Ferraton - Matthew Ferraton earned his Master of Arts in History at Cleveland State University in December 2008 and Certificate in Microsoft ...
