WxClimoEd Series, Post #1, Part 1: Understanding Global Climate Change

Hello Weather & Climate News readers! This post will be the first in what will be my ongoing education article series WxClimoEd. I hope to write educational posts on various topics related to weather and climate to help enhance your understanding of various phenomena and their impact on the environment, individuals and society. These posts will present key ideas and concepts and provide occasional linked sources to further, more detailed information.

Understanding Global Climate Change (Causes)

This article will deal with an introductory explanation of Global Climate Change as we currently understand it and the causes of it, specifically relating to human activity. Part 2 (in the next week) will discuss the known (and unknown) impacts on humanity and wildlife based on impacts on regional climates. Part 3 (in a couple weeks) will discuss mitigation efforts.

  1. Natural Climate Variability vs. Recent Global Climate Change

Earth’s climate has been evolving since the planet was born 4.6 billion years ago. These changes in Earth’s atmosphere have been largely the result of things such as biological modification of the atmosphere, volcanic eruptions, changes in ocean currents, movement of continents over tens of millions of years, variations in Earth’s orbit and other various phenomena. The most recent history of climate has featured periods of glaciation over much of the landmasses known as the Ice Ages.

Earth’s global climate has been in a “interglacial” period with a climate which warmed enough to end major continental glaciation around 11,000 yrs ago.

However, what scientists have seen in the recent climate records is a rate of change -both the climate conditions themselves and the atmospheric gases which can change the climate – at a rate accelerated and in some cases unprecedented in previous times.

Carbon Dioxide (CO2) levels going back 450,000 yrs. There have been multiple periods of glaciation and interglacial periods as part of natural change (high/low CO2 = warm/cold), but CO2 has not exceeded much above 300 parts per million until the 20th century. (NASA)

What scientists in the second half of the 20th century discovered is that for the first time in the history of human civilization we are acting as a force influencing the climate. Human-induced climate change is real.

This has been found after accounting for the natural variability in climate cycles and from our understanding of how carbon dioxide works in the atmosphere. This extremely rapid change in global temperatures, a top signal of climate change, has been driven by CO2 pollution, beginning after 1850 and the during the Second Industrial Revolution.

Graph showing the correlation between global temperatures (anomaly relative to the 1881-1910 average) and CO2 concentration 1880-2016. CO2 is known physically to be capable of “trapping” heat in higher concentration. (Climate Central)

One of the first questions which many non-scientists have about global climate change is “Well hasn’t the climate always been changing?” The answer is yes, but with a caveat…it has NOT changed this rapidly in the history of humanity on Earth (Homo sapiens sapiens have been around ~200,000 yrs). Since Earth began the process out of the last glaciation 22,000 yrs ago, global temperatures have varied up to a 4 degrees C. But this process of variability has occurred over the course of centuries to a couple of millennia because of the long cycling of natural processes. Human activity in the form of burning fossil fuels since the latter 19th century has caused around 1 degree C of warming within a 100-150 yr period. This comic comparing the average temperature of Earth to the end of the Ice Age and achievements of human civilization across millennia strongly illustrate the climate stability we’ve come to flourish under. (zoom in at the top and scroll down…it’s long, but worth the read and look!). Humans have essentially acted as a continuously spewing ‘volcano’ of carbon products. And as a result, we have compressed warming which would take nature nearly a millennia to do in recent geologic time and accomplished it within a century.

We are transforming our world before our eyes.

2. How does the greenhouse effect work?

The greenhouse effect is a simple concept, but one with major implications for us all in this major environmental issue. In Earth’s atmosphere exists gases which are chemically capable of “trapping” heat in the lower atmosphere, heating the surface. The three most significant “greenhouse gases” are carbon dioxide, water vapor, and methane. These gases in higher concentrations are most effective in reflecting infrared (heat) radiation originally emitted by Earth’s surface back to the surface as opposed to allowing it to be lost to space. If it wasn’t for this greenhouse effect, Earth would be literally completely glaciated over and very cold.

Example graphic showing the “radiation budget” and how the greenhouse effect impacts how much radiation is retained by Earth’s atmosphere. (By Wikipedia user ZooFari)

Methane is very potent, but short-lived without constant replacement as direct sunlight breaks the molecules apart. Water vapor varies seasonally with some balance because of the water cycle. Therefore carbon dioxide or CO2 ends up being the most important changing variable for warming/cooling the climate. Such changes, along with other variable cycles, have influenced previous periods of ice ages. But human “eruption” of CO2 since the 2nd half of the 19th century has led to clear changes in Earth’s atmosphere and climate.

This YouTube video shows 131 yrs of global warming (1880-2011). The “anomalous temperature” is relative to the average planetary temperature of 1880-1910. The average temperature of Earth has continued to warm above this average to record levels since 2011. The planet is known to have warmed by ~1 degree C (nearly 2 F) since the late 19th century. The most dramatic warming (as can be seen in the video) began to ramp up significantly since 1980. Depending on the scenario, human-induced warming of Earth may reach 1.5-2 degrees C (2.7-3.6 F) above pre-industrial levels by 2050 and (depending on human efforts to decrease CO2 pollution) the warming may hit 2-4+ degrees C (3.6-7.2+ F) by 2100.

3. The importance the rate of warming

Such rapid rates of warming are what alarms climatologists and those who understand the importance of climate stability for life and society on Earth. Remember the last time you saw a wholly mammoth, saber-toothed cat, wholly rhino, or an indigenous North American horse? Never because they all went extinct from the “rapid” climate change of the final end of the ice age glaciation 11,000 yrs ago. What’s “rapid”? Temperatures warmed more than 2.5 degrees C over the course of 1500 years. We may accomplish that in 150-200 yrs! Incredible. But yet the “rapid” natural changes were not non-consequential. Many more species than listed which couldn’t adapt died out over hundreds to a couple thousand years. And minor variations in global climate by 0.5 degrees C or less – or even significant regional variations which barely showed up on the global signature – have led to major losses in agriculture and economics producing stresses on some nations (poverty, famines, wars) and in some cases, isolated civilizations simply died out. Having such rapid, unprecedented warming is a cause for concern because too many species (and many socio-economic or geographically vulnerable peoples) may face significant harm in the face of an inability to adapt to transforming climate regimes.

In Part 2, later this week, I’ll discuss the effect climate change has on regional climates and likely impacts being faced by humans and wildlife as the climate continues to heat up extremely quickly.

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The US is burning badly in 2017.

2017 at year-to-date is currently ranking at the 2nd highest acres burned on record! And much of that burning is happening in the forests of Alaska where climate change is having huge effects on both precipitation and warming temperatures.

I have to admit, I was surprised to see this amount of acreage burned. But, in reality it is really not that surprising. A very positive winter in terms of precipitation ended much of the drought in CA and the West. However, this was allowed for abundant vegetation growth for active fuels available. And now that summer long since come, the dry season means numerous fires from human activity and lightning from dry thunderstorms. I’m addition, abnormally dry soil conditions have begun to redevelop over the Four Corners States as well as rapidly deteriorating drought on the high plains of Montana.

National Drought Mitigation Center (University of Nebraska-Lincoln)

Here’s Alaska’s situation if you were so curious. They have become abnormally dry to moderate drought recently across much of the state.

There are 48 active fires across the Western US as of today (according to the Weather Channel).

If there are positives, it is that for parts of the Desert Southwest, the Monsoon, which can bring potentially fire starting thunderstorms can also bring beneficial rains to moisten soils and fuels, so as long as there isn’t too much falling at once (flash flooding from some storms is a common problem every year).

Wildfires have and are expected to continue to statistically increase in a warming world because of global climate change.

Northern Plains becoming hard hit by severe to extreme drought

The Northern US Great Plains into the southern Canadian Prairies are suffering from a growing drought problem. The National Drought Mitigation Center at the University of Nebraska-Lincoln released their weekly drought monitor which updates on the drought situation for the entire country (every Thursday based on Tuesday data). Drought overall across the United States has begun to grow in coverage and intensity. This can happen just from the local abnormalities in a summer season. However, a persistent pattern of dryness has developed over the Northern Plains beginning in May where significantly below normal rainfall has caused soils and hydrologic sources to begin to dry out.

I took a look at some meteorological stations for their recent climate records. Rapid City, SD (currently in the moderate drought zone) is running 3.37 inches below normal in rainfall for the May 1st-July 21st period. In Bismarck, ND (in severe drought) is even worse at 4.01 inches below normal for the same period. May dryness hit the region hard with a major monthly deficit then it simply continued into the summer. At least moderate drought covers ~28% of the above region (ND, SD, NE, KS, WY, CO). Moderate conditions can result in some damage to crops and reduction in stream/river flows and lowering of lake levels. Extreme – which now exists in spots of southwest ND – can mean widespread and devastating agricultural losses and severe reductions in hydrologic sources.

Above average temperatures likely over the Great Plains (and rest of the country) over the next 3 months. (Climate Prediction Center)
Meanwhile, there are equal chances (~33% each) for above, near, or below normal precipitation during the same 3 month period. (Climate Prediction Center).

Obviously, “equal chances”- which is based on the expected evolution of various climate patterns – means that there could very well be above average rainfall, which the region really needs at this point to get out of the growing deficit. However, if it ends up being near-normal, they may continue to simply lag behind with similarly bad impacts. Below normal means a worsening and spreading of drought conditions and further difficulty removing the existing drought (anyone remember the difficulty California had in getting out of drought?). Folks in these areas should be prepared for any further water restrictions and do what they can now to conserve in case the dryness lasts longer than expected.

Elsewhere, dryness and moderate drought has begun to spread into parts of the Intermountain West and Four Corners.

Quick update from the Eastern Pacific tropics…new tropical depression! Tropical Depression Ten-E is rolling around between Tropical Storm Greg and TD Nine-E. It’s expected to become a tropical storm in the coming days as it generally moves westward over the open ocean. So there are now 4 existing cyclones in the tropical North Pacific east of 180 longitude. Although Fernanda is dying quickly over cooler waters and dry mid-level air and will likely dissipate by tomorrow.

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Good weekend to you all!