March 2021

A trip through the science of a warming planet

This article is the first in a series focused on the causes and consequences of a warming planet

planet EarthIs the Earth getting warmer? If it is, what is causing it to warm? Moreover, if it is getting warmer, what impact will it have on the Earth’s climate? Most important, how will a changing climate impact us?

Many people believe that the planet is getting warmer and the warming is caused by human activity. Moreover, they believe that the warming is causing the earth’s climate to change in ways that are a threat to us and future generations. Some prefer to believe that the planet is not warming. Others believe the world is warming but don’t believe it is caused by human activity. Many people are somewhere in the middle and aren’t sure what to believe.

Join me for a trip through the current scientific evidence of a warming planet and the resulting changes in the planet’s climate. This series is an attempt to clarify these issues based on science from leading institutions around the world. Examples include the National Aeronautics and Space Administration (NASA), the National Oceanic and Atmospheric Administration (NOAA), the Intergovernmental Panel on Climate Change (IPCC) among others

The series is also an attempt to help you understand these concepts by using common, everyday examples. Although the Earth and its climate are complex, many of the forces that drive the world’s climate are familiar to us because they are the same ones we experience in our everyday lives.

Before we start, we should clarify the commonly used terms of global warming and climate change. Although these terms are often used interchangeably, they have different meanings. Global warming is the increase in the average temperature of Earth's near-surface air and oceans. As the Earth warms, it causes changes in the Earth’s climate. Changes in the Earth’s climate include rising sea levels, changing precipitation patterns, increasing severity and occurrence of extreme weather events such as droughts and floods, and many others.

Understanding the world of research

Scientific research increases our understanding of the Earth and the environment in which we live. It requires careful investigation and analysis.

One research study does not make something a fact. The results of an individual research study often just raise questions for further investigation. To establish something as a fact requires a "body of research." Not until several studies, focused on a question from various perspectives, come to the same conclusion, do scientists conclude with reasonable confidence that something is a fact.

In this series, we will focus on "peer-reviewed" research. These are scientific research studies where other scientists (peers of the researcher) are anonymously called upon to review the research to see if it was done properly. This review doesn’t mean that the research should show a predetermined result. Rather, it means that the research followed proper "scientific methods and procedures." If the reviewers find errors in how the research was conducted, the research study may be rejected and the reputation of the scientists who did the research may be questioned.

If the research is accepted by the reviewers and published in a research journal, other researchers will see if they can come up with the same results using different techniques or data sets. If the results cannot be replicated, the reputation of the researcher, along with that of the peer reviewers and the research journal, may be called into question.

Climate deniers often claim that climate researchers skew their research results to come up with findings that will promote themselves and increase their chances of obtaining funding for further research. But the process outlined above will cause researchers to be conservative in their findings because they do not want to suffer the consequences of being proven wrong.

Research concepts that are often misunderstood and used incorrectly are correlation and causation. Correlation is a relationship between two variables. For example, you may have put fertilizer on your garden during a rainy period and your garden plants grew larger. So you may conclude that there is a correlation between the fertilizer application and the growth of the garden plants.

With causation, a change in one variable causes a change in another variable. Although there is a correlation between fertilizer and plant growth, there is no proof that the application of the fertilizer was what caused the plants to grow bigger. Your garden may already have sufficient fertilization but was in need of water. So, although the garden plants grew larger when the fertilizer was applied, the fertilizer did not cause the larger plant growth. It was the rainfall that caused the plants to grow larger.

It is common for people to assume causation just because correlation exits. This mistake usually leads to faulty analysis.


Don Hofstrand, retired extension value added agriculture specialist, agdm@iastate.edu
Reviewed by Dr. Eugene Takle, retired professor emeritus Iowa State University

Author

Don Hofstrand

retired extension value added agriculture specialist
View more from this author
Reviewed by

Dr. Eugene Takle

retired professor emeritus Iowa State University