Kaylynne M Glover, PhD

NASA: What is Climate and Climate Change? 
IPCC: Intergovernmental Panel on Climate Change
United Nations Framework Convention on Climate Change

Consensus Statements of Major Scientific Organizations

American Academy for the Advancement of Science (AAAS)
American Chemical Society
American Geophysical Union
American Meteorological Society
American Physical Society
Geological Society of America
The U.S. Global Change Research Program
U.S. National Academy of Sciences

Joint Statements

Joint Statement from the 31 Major U.S. Scientific Organizations to Congress
The Intergovernmental Panel on Climate Change
The National Academies of Sciences, Engineering, and Medicine

Climate change. Global warming. Which is it? Well, good question. As it turns out, it’s both. That’s because one causes the other.

Here’s the basics:

As global temperatures increase (“global warming”), it causes the general patterns of weather that happens in each area – it’s climate – to change. What they’ve been accustomed to – like how much snow they get or when the first frost occurs – changes, and this impacts the life there.

And whether they can weather the new weather is hard to say – includes us humans, who have come to rely on things like certain crops being able to be grown in certain areas. We’ll have to adjust because we don’t have any other places to go, and how smoothly that adjustment happens depends on the policies we enact.

This is why climate change, a scientific reality, is also a political issue.

If you want to know more about these processes, I’ve expanded a few of the major concepts here.

The Science (Simplified)

Global Trends

Peer-Reviewed References

Consensus Statements

The Science (Simplified)

Understanding climate change starts with an understanding of energy. The sun provides energy to the earth allowing for life to exist, and excess energy is reflected back into space. Thankfully, several types of gases in our atmosphere reflect this energy back to the earth, helping it retain its heat. These gases, known as greenhouse gases, have allowed the earth to have a hospitable climate. The amount of greenhouse gases in our atmosphere has a significant impact on earth’s temperatures – too low, and the earth cools; too high, and the earth warms.

Human industry since the mid-1800’s has begun releasing significant quantities of greenhouse gases, and most of the heat being released into space is being reflected back. As a result, the earth is heating at an unprecedented rate. We know this not only through measurements of greenhouse gases and temperature changes, but by the influence that it is having on life.

One major impact is that on ocean life. The ocean absorbs approximately 90% of earth’s excess heat, and oceanic temperatures have been rising because of it. In turn, this affects oceanic life. One of the biggest impacts is on coral reefs: coral reefs are home to over 25% of oceanic life, they play a key role in all oceanic life. But coral reefs are easily stressed by temperature changes, and when the temperature gets too warm (or too cold), they undergo “bleaching”, which makes them very frail, and they often die. Coral bleaching is at an unprecedented rate, and reefs are suffering because of it.

The ocean suffers for another reason: not only does the ocean absorb excess heat, it also acts as a “carbon sink,” and absorbs at least 25% of the carbon dioxide we release. This changes the pH of the ocean, making it more acidic. Even small changes in pH can be disastrous, and for ocean life, other dangers include dissolving shells and fragile, non-repairing corals.

Global warming is also affecting land life as well. The home ranges of animals are shifting as are migratory patterns, and many are facing extinction as they lose access to favorable habitats. This affects the food sources that are available, diseases that emerge, and can shift entire biomes (turning woodlands into grasslands, etc.).

One of the most frequently discussed impacts of global warming is its impact on ice and snow. Increased temperatures result in decreased snow and ice cover. Not only does this impact land and ocean, it also has a compounding affect on global warming. Snow and ice is very reflective; without it, the ground absorbs 4-6 times as much energy. As we lose snow and ice, the earth absorbs more heat, we lose even more snow and ice. Called the “Ice-Albedo Feedback,” this means that the amount of snow and ice affects earth’s cooling and heating more than any other land feature.

Global warming will have significant impacts on human life. Not only will our food sources and living conditions change, including relocating to areas more hospitable (see also here), but increases in the frequency and severity of major storms are not only expected, but are also occurring. All industries dependent upon wildlife and environment – including tourism, fishing, and hunting – will be seriously impacted, all of which has serious economic cost.

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Global Trends

Atmospheric Temperature Increases:

  • Since 1970: 0.8 degrees C (1.5 degrees F) (NASA)
  • Since 1900: 1.1 degrees C (2 degrees F) (NOAA, UEA, NASA)
  • 16 of the 17 hottest years on record have occurred since 2001 (NASA)
  • Currently matching climate model predictions (NASA)

 Decreasing Ice, Snow, and Glacial Cover

  • Ice sheets declining at an accelerated rate (NSIDC)
  • Continents losing mass (NASA)
  • Glacial shrinking, decreasing in thickness and mass (NSIDC)
  • Drop in snow cover (extent, depth, and snow water equivalent) beginning 1967 and accelerating after 2003 (NSIDC)

Oceanic Impacts:

  • Ocean has been increasing in temperature, with half of the heat over the past 150 years occurring within recent decades (NOAA)
  • Significant increases in sea level caused by melting ice and show: 8 inches since 1900, and double that rate since 1990. (IPCC)
  • Ocean Acidification: Increases in carbon dioxide absorption acidifies the ocean, causing rippling effects throughout the oceanic ecosystem, destroying sea life and industries that rely on them (NOAA)

 Impacts on Humans:

  • Extreme weather events, including heat waves, droughts, hurricanes, tropical storms, blizzards, and floods are becoming increasingly common and more intense (NOAA) (C2ES) (NCA)
  • Many diseases are linked to environmental and climate changes, and scientists are predicting increases in diseases as a result of climate change (WHO)

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Peer-Reviewed References

Not everyone has access to the raw data on climate change. My goal here is to create an easy-to-access repository of some of the major climate change studies that are available to the public, though perhaps not always easy to find. Please feel free to contact me if you have suggestions, either that links are broken or that there are others to include. Some of the earliest studies documenting climate change: 

Effects of Climate Change: 

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Consensus Statements

There is a scientific consensus on climate change: it is happening, and humans are largely responsible. Not only have several scientific organizations issued their own position statements on climate change, but they have banded together to create joint statements affirming the reality that is climate change, hoping that by doing so, policy makers will respond in kind.

Consensus Statements of Major Scientific Organizations

American Academy for the Advancement of Science (AAAS)
American Chemical Society
American Geophysical Union
American Meteorological Society
American Physical Society
Geological Society of America
The U.S. Global Change Research Program
U.S. National Academy of Sciences

Joint Statements

Joint Statement from the 31 Major U.S. Scientific Organizations to Congress
The Intergovernmental Panel on Climate Change
The National Academies of Sciences, Engineering, and Medicine

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