Over the last decade, global climate change (often referred to as ‘global warming’) has moved considerably into the public’s attention. The concept, being both scientific and political, has not only been a topic of increased research, but has appeared in presidential debates, T.V. adds, numerous movies, and even charity work. Given its increased prominence in society, one would think that many would have a more complete understanding of the fundamental truths that encompass this broad area, but this is not the case. Perhaps due to the very media and politicians that have popularized the term, a large percentage of Americans remain skeptical about the issue, many without a firm reasoning to do so.
As a scientist who has studied climate change in the remote places of the Earth for over a decade, I stand firmly that the scientific evidence supporting climate change to be a real and potentially dangerous threat is overwhelming; that climate change is indeed occurring, and that man is the main mechanism to blame. I am not alone in this belief, despite the fact that media and other popular outlets may try to convince you otherwise.
Ultimately, the debate about climate change isn’t usually about whether or not the Earth is warming; nearly every scientist studying the Earth’s climate and the majority of non-scientific lay people agree in this assertion, despite (small and inconsequential) errors in observations over the last century. Based on the Intergovernmental Panel on Climate Change (IPCC), a body of the top climate scientists worldwide, the Earth as a whole has warmed 0.74°C (1.33°F) over the last century, and this warming rate is accelerating each decade. Using ice cores and other long-term measurements that are natural recorders of temperature changes, there is less than a 10% chance that any other 50 year period during the last 500 years has been as warm as the last 50 years. In a long-term record from an Antarctic ice core, the last century clearly stands out as unusually warm compared to the temperatures during the last 600,000 years. These, and other telling pieces such as sea level rise, glacial retreat, and permafrost melting, are strong evidence that the world has indeed been warming.
The debate then stems to the causes of such warming, and herein resides the divide among a few scientists, as well as the lay public. Still, despite what public sources may have you believe, the majority of scientists believe that man, through increases in heat-trapping greenhouse gases (such as carbon dioxide, methane, and nitrous oxide) spurred primarily from fossil fuel combustion, is the main cause. A considerably smaller sanction of scientists, as well as a large population of the American public, endorse the idea that the warming observed in the instrumental and other records is due to natural cycles in the Earth’s climate rather than any dominant man-made component. While it is very true that natural variability plays a large and central role in the climate from one year to the next, long-term trends in temperature from natural variability arise primarily from glacial (ice ages) to interglacial (ice-free) periods in Earth’s history. Those supporting the claim that the ongoing warming trend is due to natural causes largely suggest that our warming is tied back to the fact that we are still emerging out of the last ice age, which ended roughly 20,000 years ago.
Who are we to believe? Scientists make their assertions that man is primarily to blame through investigating numerous computer simulations of Earth’s climate, both from the past as well as several centuries into the future. These simulations are done by climate models, which attempt to predict climate by incorporating parameters and variables known to influence changes in the Earth’s atmosphere, ocean, land surface, and ice cover. The major benefit of using these simulations is that each component can be added or removed from the simulations in order to quantify that particular component’s role in forcing changes. Using these so-called sensitivity simulations, climate scientists have determined that changes in greenhouse gas concentrations are the dominant mechanism leading to the observed changes, and that natural mechanisms in the Earth’s climate system (those that exist independently of man) cannot alone explain the magnitude of the changes. Although these simulations are not perfect, the results are confirmed from over 5 dozen simulations from nearly 2 dozen different models generated by multiple countries worldwide. Indeed, being one of the few tools we have to attribute changes in temperature, the fact that these simulations all tell that greenhouse gases (and primarily carbon dioxide) are the dominant mechanism clearly demonstrate man’s important role in changing climate.
What then shall we do about this potentially dangerous crisis? First and foremost is increased education and awareness. We must continue to advocate good, credible science and increase awareness about this issue, including our own continuing education as research quickly progresses. Second, we must take our own steps to reduce, reuse, and recycle so that our carbon footprint is reduced; if multiple people adopted this mindset, the global demand for energy and resources could be substantially reduced. Lastly, we must continue to endorse leaders who have the same concerns for the environment as we do, hoping that long-term change and policy may eventually result. Altogether, we must strive to make this planet better. Indeed, when the 2007 IPCC report was a co-recipient with Al Gore of the Nobel Peace Prize, it was recognized internationally that understanding and promoting climate change is a prominent way to achieve global peace, avoid conflict, and protect and preserve the planet we all call home.
Dr. Ryan Fogt is an Assistant Professor of Meteorology in the Department of Geography. He is also the director of the Scalia Laboratory for Atmospheric Analysis. His research interests span a wide range of topics on climate variability and change, with a particular focus on Antarctica.