Climate change means the unusually rapid warming of the atmosphere and its scientifically documented effects around the world. The warming is measurable: although annual local weather patterns vary, the average global temperature has increased by nearly 0.8ºC (1.5º F) in the last 100 years. This might not sound like much, but even small temperature changes occurring worldwide have a noticeable effect on the climate, which affects habitats for all organisms, including humans. In addition, the pace of change is increasing: most of the rise in average global temperature has occurred in the last few decades.
Climate change and the human contribution to this change is sometimes denied or depicted as an uncertainty. However, according to the American Association for the Advancement of Science (see References and Further Reading), climate change is not controversial: 97 percent of climate scientists are certain that human-caused climate change is occurring. Climate research is continuing, with scientists and engineers working to predict the consequences of climate change and finding ways to overcome its negative impact.
People around the world, in cities and in rural areas, are experiencing more extreme temperatures, stronger storms, and loss of land from rising sea levels. Some of the most dramatic effects of climate change are related to water: either too much water that results in flooding or too little that results in droughts and wildfires.
For example, even slightly increased temperatures that result from climate change will melt sea ice. Both melting sea ice and higher temperatures increase the volume of the ocean. Greater ocean volume means higher levels of water along coastal areas, which adds to erosion of these areas. In addition, melting sea ice can lead to global changes in water circulation: water from the melted ice forms a layer at the sea surface that is less dense than the underlying water because it is less salty, potentially preventing the patterns of deep ocean currents from rising to the surface. Melting sea ice also speeds up the warming of the Arctic because water absorbs 80 percent of sunlight, which is about the amount of sunlight that a cover of sea ice reflects.
In this collection, students will use photographs as data to observe and identify changes over time in water-related features such as coastlines or glaciers. They will use photographs to prompt discussions on the consequences of climate change to humans and habitats. They might even use photographs as motivation to explore how they can be citizen scientists and engineers in studying climate change and mitigating its negative effects in their own communities.
Note: The term “weather” refers to short-term atmospheric features such as precipitation, wind, and temperature. “Climate” means the long-term weather patterns of an area; for example, average temperatures over many years.
Older references might use the term “global warming” to refer to climate change. Global warming refers to the heating effect of greenhouse gases accumulating in the atmosphere. Scientists study more than just how temperature is affected by human activity, however. To emphasize that human activity does more than just influence temperature, the more common term for rising average global temperatures and its effect is “climate change.”