Introduction: What is climate change?

Weather

COURTESY: NOAA

In order to understand climate change, we need to start with the basics. This blog aims to do just that – break down the complex science of climate change in an easy-to-understand way — without the fancy terms, politics or conspiracies. Just the science.

There are thousands of textbooks and peer-reviewed articles that go into much more detail, but this post’s purpose is not to overwhelm you with the technicalities or ‘doom & gloom’. The goal to scrape the surface, to give you insight into the constantly-evolving study of climate change.

Think of this as a ‘Beginner’s Introduction to Climate Change.’

The basics

Simply put, climate can be thought of as ‘long-term weather’ – a 30-year-average (if not, longer) of temperature, precipitation and other meteorological variables at a certain location. Think of weather as “Is it going to rain today?” and climate as “Do we usually see rain in January?”

Weather is in this instant, and climate is what is typical, usual or normal for this time of day/month/year.

The climate has been changing since the beginning of our planet’s formation. We know this by examining ice cores, fossils, tree rings, etc. And although these changes have been naturally-driven for thousands of years, data now shows increasing evidence that humans are contributing to the rise in global temperature and as a result, shift in climate.

The consensus: Multiple studies in peer-reviewed science journals show that 97% or more of actively publishing climate scientists agree that “climate-warming trends over the past century are extremely likely due to human activities”. Within the vast majority of the science community, the issue is not “Is the Earth warming?” or “What is causing the Earth to warm?”… the question is “What can we, as humans, do to minimize our impacts on our planet and adapt to the changes?”

Natural causes

Tiny variations in Earth’s orbit and tilt can change the amount of solar radiation we receive from the Sun. Our atmosphere and ocean work together to keep the Earth balanced given these seemingly subtle changes in radiation. It’s this balancing act between what comes in (solar radiation) and what goes out (longwave radiation) by our atmosphere and oceans that keeps our planet habitable.

For example, if the Earth is positioned in such a way where less solar radiation (Sun’s energy) is received, summer temperatures will fall, winter ice does not melt, ice sheets grow and an ice age begins. What’s more – ice absorbs less energy (heat) than land which further enhances the cooling effect. It’s important to note that this doesn’t happen overnight. This is typically on the time scale of thousands of years. To put this into perspective, in the last 650,000 years, there have been 7 recorded ice ages, the last ending 11,700 years ago. (Some scientists believe we are already overdue for our next one but the effects have been countered by our planet’s current warming trend.)

We can also attribute certain climate changes by recognizable patterns in our atmosphere and oceans. (Ex. El Nino – warmer equatorial waters in the Eastern Pacific can lead to warmer, wetter winters in Texas.) On a smaller scale, the frequency of high/low pressure systems over certain areas can also be considered part of a location’s climate (ex. Indian Monsoon or North American Monsoon).

Anthropogenic (human-caused)

Some of the naturally-occurring gases in our environment (namely carbon dioxide, methane, nitrous oxide, etc.) trap heat in our atmosphere, essentially acting as a ‘blanket’ around our planet. This goes back to the atmosphere’s portion of the ‘balancing act’. These gases help keep our temperatures from plummeting to uninhabitable levels overnight when sunlight is not received. This is called the Greenhouse Effect.

The focus for human-caused climate change revolves around the Greenhouse Effect. Since the Industrial Revolution, humans have been pumping more and more of these greenhouse gases into the atmosphere. The science tells us these are heat-trapping gases. If we are adding more of these gases to the atmosphere (via our vehicles, land use, burning of fossil fuels, industrial processes, etc.) our planet will warm. It is a cause-and-effect relationship.

One of the strongest pieces of evidence for human-induced climate change is the planet’s record of carbon dioxide concentration.

The graph above shows monthly mean carbon dioxide levels measured at Mauna Loa Observatory, Hawaii, which holds the longest recorded direct measurements of CO2 in the atmosphere. The carbon dioxide concentration (red) is measured in parts per million… with the black line indicating the annual average. The trend shows a significant increase in our atmosphere’s carbon dioxide concentration. In fact, our carbon dioxide level reached a historic high just last month. In May 2020, a peak value of 417.1 ppm, 2.4ppm over May 2019’s peak of 414.7 ppm. More on this here.

Evidence

How do we now the climate is rapidly changing? The evidence is compelling. (This part can be hard to comprehend and even harder to accept as our reality – but it’s important to put numbers to the facts):

  • The planet’s average surface temperature has risen about 1.62 degrees Fahrenheit since the late 19th century
  • The top 700 meters (about 2,300 feet) of our oceans are showing a warming of more than 0.4 degrees Fahrenheit since 1969
  • Greenland lost an average of 286 billion tons of ice per year between 1993 and 2016, while Antarctica lost about 127 billion tons of ice per year during the same time period
  • The rate of Antarctica ice mass loss has tripled in the last decade
  • Satellite observations reveal that the amount of spring snow cover in the Northern Hemisphere has decreased over the past five decades and that the snow is melting earlier
  • Both the extent and thickness of Arctic sea ice has declined rapidly over the last several decades
  • The number of record high temperature events in the United States has been increasing, while the number of record low temperature events has been decreasing since 1950
  • Since the beginning of the Industrial Revolution, the acidity of surface ocean waters has increased by about 30 percent
  • The amount of carbon dioxide absorbed by the upper layer of the oceans is increasing by about 2 billion tons per year
  • Global sea level rose about 8 inches in the last century. The rate in the last two decades, however, is nearly double that of the last century and is accelerating slightly every year.

Statistics courtesy of NASA.

The effects

Climate affects everyone and everything – whether direct or indirectly. It impacts our way of life, our pocket books, our environment, our economy, etc.

More often than not, climate change impacts are not immediate nor tangible, which makes it easier for some people to ignore the urgency of the issue. You may not be able to feel a day-to-day rise in temperature… but a global rise in temperature, even minute, can be detrimental. You may not notice a single spring season seeming shorter or warmer… but a quicker transition to summer or a prolonged winter over the years could be catastrophic for a particular crop/industry.

The bottom-line

As noted above, there is a part of climate change that is natural. However, the rate at which our climate is currently changing is proving to be unnatural. An overwhelming majority of climate scientists believe that human actions are a large contributor – and the evidence/numbers/statistics are all there to prove it.

The good news? There are certain actions we, as society, can take to help mitigate our effects on the planet. There are also solutions aimed at ‘back tracking’ on some of the harmful effects already playing out.

Look for more on this topic and other climate change related articles on the KXAN Weather blog in the future.

For more information, visit NASA’s Global Climate Change website.

Copyright 2020 Nexstar Broadcasting, Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.

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