Tag: Global warming

Counting on … day 195

18th  October 2024

Scientific concern about the adverse affects of climate change in the Earth capacity to absorb carbon dioxide, extends to the land as well as the oceans. 

“In 2023, the hottest year ever recorded, preliminary findings by an international team of researchers show the amount of carbon absorbed by land has temporarily collapsed. The final result was that forest, plants and soil – as a net category – absorbed almost no carbon…

“A paper published in July found that while the total amount of carbon absorbed by forests between 1990 and 2019 was steady, it varied substantially by region. The boreal forests – home to about a third of all carbon found on land, which stretch across Russia, Scandinavia, Canada and Alaska – have seen a sharp fall in the amount of carbon they absorb, down more than a third due to climate crisis-related beetle outbreaks, fire and clearing for timber.

“Combined with the declining resilience of the Amazon and drought conditions in parts of the tropics, the hot conditions in the northern forests helped drive the collapse of the land sink in 2023 – causing a spike in the rate of atmospheric carbon.”

This shortfall or decline in the carbon absorbing capacity of the natural world is a serious concern when we are relying on that capacity to achieve a net zero target. Indeed if this persists, we will have to reduce our human enduced carbon emissions faster and at a greater rate.

Counting on … day 194

17th October 2024

Blue carbon is not just the carbon absorbed in the seas around our coasts. It is an ongoing process that encompasses oceans and deep seabeds. However scientists are concerned that the process is being adversely affected by rising temperatures.

“It begins each day at nightfall. As the light disappears, billions of zooplankton, crustaceans and other marine organisms rise to the ocean surface to feed on microscopic algae, returning to the depths at sunrise. The waste from this frenzy – Earth’s largest migration of creatures – sinks to the ocean floor, removing millions of tonnes of carbon from the atmosphere each year.

“This activity is one of thousands of natural processes that regulate the Earth’s climate. Together, the planet’s oceans, forests, soils and other natural carbon sinks absorb about half of all human emissions. But as the Earth heats up, scientists are increasingly concerned that those crucial processes are breaking down….

“Greenland’s glaciers and Arctic ice sheets are melting faster than expected, which is disrupting the Gulf Stream ocean current and slows the rate at which oceans absorb carbon. For the algae-eating zooplankton, melting sea ice is exposing them to more sunlight – a shift scientists say could keep them in the depths for longer, disrupting the vertical migration that stores carbon on the ocean floor.”

https://www.theguardian.com/environment/2024/oct/14/nature-carbon-sink-collapse-global-heating-models-emissions-targets-evidence-aoe?CMP=Share_iOSApp_Other

Counting on … day 52

23rd February 2024

Keeping the temperature rise – global warming – within 1.5C necessitates constraining the carbon dioxide (and other greenhouse gas) emissions we release into the atmosphere. The diagram below shows the correlation between global temperatures and carbon dioxide concentrations in the atmosphere. 

Keeping global warming within this window involves both reducing the amount of greenhouse gases we emit and enhancing processes that absorb such gas emissions. An example of the first would be reducing – or even cutting out entirely – the burning of fossil fuels; an example of the second would be reinstating woodlands and wetlands. 

Counting on … day 50

21st February 2024

1.5C is the level of warming within which we should be trying to stay if we are to avoid an unbearably worse deterioration of the global climate. This figure is the product of over 6,000 scientific references, and was prepared by 91 authors from 40 countries. https://en.wikipedia.org/wiki/Special_Report_on_Global_Warming_of_1.5_°C

This is not to say that even with global warming at 1.5C there won’t be adverse effects. The extreme hot summer temperatures, floods, wild fires, droughts, and storms that we have experienced over the last few years will now be the norm. Glaciers, sea ice and ice caps will continue to melt and disappear, causing rivers to dry up in the summer, and elsewhere raising sea levels. The change in climate is already altering natural habitats reducing numbers of plants, birds, animals, insects etc, and having similar adverse effects on agriculture. Food and water security are already being threatened. Warming oceans is reducing marine life. All this will increase as temperatures rise.

Each fraction of a degree of further global warming  will accentuate these problems for all life forms. The charts show  how much greater would be the effects of 2C warming over 1.5C. 


Counting on … day 49

20th February 2024

Global warming is defined by the IPCC as “an increase in combined surface air and sea surface temperatures averaged over the globe and over a 30-year period. Unless otherwise specified, warming is expressed relative to the period 1850–1900, used as an approximation of pre-industrial temperatures… For periods shorter than 30 years, warming refers to the estimated average temperature over the 30 years centred on that shorter period…” (1) https://www.ipcc.ch/sr15/ An IPCC Special Report on the impacts of global warming of 1.5°C 2018

The chart below shows a baseline which is the average (mean) of the combined surface air and sea surface temperatures for the period 1850-1900. The bred and blue columns shows the annual deviation around that base line. Between 1850 and 1900 the blue and red columns cancel each other out. The increasing number and height of the red lines thereafter show the extent of global warming.