Source: Wix Imagery 2024
Greenhouse Gases
Climate change caused by very large human-sourced greenhouse gas (GHG) emissions is internationally recognised as a major threat to global ecosystems and the human population on Planet Earth. How has this come to be?
The most common GHG on Planet Earth are water vapour, nitrous oxide, methane, and carbon dioxide. These gases have a heat trapping effect in the atmosphere. Fluorinated gases (HFCs, PFCs, SF6) used in air conditioning and propellants are man-made types of GHG which occur in small quantities, but have a very high heat trapping effect, Figure 1.
Figure 1: Common Greenhouse Gases
Source: NASA
Greenhouse Gas Effects
GHG produce a heat trapping effect by forming a 'blanket' around the Earth which partially prevents sun rays from bouncing off the Earth back into space, similar to how a greenhouse traps heat, Figure 2.
Figure 2: Greenhouse Effect
Source: Royal Society ex USEPA
The natural GHG effect is a normal process which acts to keep the Earth's surface at an average temperature of +15 °C. Without "normal" GHG warming, the Earth's surface temperature would be about −18 °C. For over 10,000 years, all life on Earth has become adapted to stable seasonal cycles of weather and growth based on this normal level of GHG warming, a result of the natural carbon cycle operating across the planet.
Natural Carbon Cycle
Normally the Earth's natural carbon cycle operates in a balanced way like this, Figure 3.
Figure 3: Carbon Cycle
Source: USGS
Problems occur when the delicately balanced Earth ecosystem is disturbed. Up until the 1850's, the Earth's natural carbon cycle proceeded in a predictable and stable manner.
Massive jump in emissions following Industrial Revolution
But since the Industrial Revolution started in the mid-1800's, human-sourced GHG has been emitted to the atmosphere in rapidly increasing quantities now approximately ten times that emitted in 1850. Climate change problems from fossil-fuel burning were first predicted in New Zealand in an article published in the 14 August 1912 issue of the Rodney and Otamatea Times, Waitemata and Kaipara Gazette, author unknown, Figure 4.
Figure 4: New Zealand Newspaper Article on Climate Change
Source: Rodney and Otamatea Times 14 August 1912
Since 1912, global emissions - or humanity's carbon footprint - have increased five times from 10 billion tonnes per annum to 50 billion tonnes per annum. Figures 5 and 6 show emissions by world region and source.
Figure 5: GHG Emissions by region1850-2022
Source: Our World in Data
Figure 6: GHG Emissions by source 1850-2022
Source: Our World in Data
Fossil-fuel burning is the main source of carbon dioxide, which is the dominant GHG, Figure 7.
Figure 7: Sources and Sinks 1850-2022
Source: CSIRO
Dangerous climate change
This massive increase in very large amounts of GHG over only 174 years has lead to, by Planet Earth's ecosystem standards, a very rapid increase in global temperature in a very short time, giving plants, animals and humans very little time to adapt. The overload of abnormal GHG emissions has resulted in deadly effects on the Earth's ecosystems, combining to reduce the life-supporting capacity of the planet, Figure 8.
Figure 8: Climate Change Effects
Source: World Affairs Council of Harrisburg 2022
Effects of immediate concern relate to unstable abnormal weather patterns created by the overload of GHG across the entire planet. The atmosphere, land, and sea have now absorbed about as much GHG as they can, and the Earth's ecosystem is changing to adapt to GHG overload. The earth's entire weather system is disturbed, with normal seasonal cycles changing to patterns not seen before in human history. The Earth's average temperature is now hotter than it has ever been, measured on 13 July 2024 at 17.23° C (63.01° F); and the content of carbon dioxide in the atmosphere is higher than it has ever been at 426.91 parts per million (ppm) at Mauna Loa (Hawaii) compared to 317 ppm in 1960, a 35% increase in only 64 years .
Figure 9: Melting in the Andes
Source: IFL Science 2 August 2024
Abnormal droughts, floods, fires, heat waves, more powerful hurricanes, melting glaciers, melting snow and ice fields, changes in flowering and fruit-producing seasons for food plants, rising sea levels, changes in ocean acidity that may prevent formation of shells for sea life, bleaching of coral reefs (because the water is too hot for the algae hosted by corals), and even increases in earthquakes (because the sea is heavier with more water in it) are all occurring. Rich, middle class, and poor people are literally losing their lives to climate change in abnormally powerful storms, floods and fires, with the poorest low-lying human communities being affected the worst.
Figure 10: Tuvalu Going Under
Source: Tuvalu Foreign Ministry 2021
Planet Earth responds only to the Laws of Physics
This is the most important message in this article. It is critical to understand that Planet Earth's life-supporting systems respond only to the Laws of Physics. Human opinions, politics, knowledge, marketing spin, professional denial, lobbying, pseudo-science, economics, personal and public objectives have no effect on the Laws of Physics. The atmosphere, oceans, land, and living systems they sustain will change to adapt to a warmer world depending on their biophysical limits. Plants and animals will adapt, if they can. If they can't, they will become extinct.
In short, the more GHG emitted, the hotter the planet will get, triggering certain tipping points for different systems. Many of these tipping points we do not understand and cannot predict. Once a tipping point is breached, slow or rapid, permanent, possibly lethal, and or unrecoverable change will occur. Only absolute emissions count in a warming world.
Our next article will examine how much progress has been made in reducing absolute emissions, and the effects that this is having on climate change patterns and impacts.
Contact us with any queries or topics you would like to see addressed in future articles at info@greenxperts.co.nz.
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