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Author Topic: Does climate change mean a greener Earth?  (Read 1329 times)

Offline Tim the Plumber

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Does climate change mean a greener Earth?
« on: 20/05/2016 11:33:25 »
Quote
Rise in CO2 has 'greened Planet Earth'
Rise in CO2 has 'greened Planet Earth' - BBC News

Carbon dioxide emissions from industrial society have driven a huge growth in trees and other plants.

A new study says that if the extra green leaves prompted by rising CO2 levels were laid in a carpet, it would cover twice the continental USA.

Climate sceptics argue the findings show that the extra CO2 is actually benefiting the planet.

But the researchers say the fertilisation effect diminishes over time.

They warn the positives of CO2 are likely to be outweighed by the negatives.
So they say that the positive effects get less better over time. OK. We'll just take the good and not expect it to get that much better than now but not go back to the bad old days.

Those negative effects though.. those would be the ones which show no signs of actually happening....

P.S. You will have to google the actual BBC article since I can't post links here.
« Last Edit: 20/05/2016 22:51:03 by chris »


 

Offline evan_au

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Re: Does climate change mean a greener Earth?
« Reply #1 on: 22/05/2016 04:13:30 »
If you live in Siberia or northern Canada, a warmer Earth would result in a greener landscape.

However, if you live on the edge of a desert - in China, Africa, USA or Australia, a warmer climate means more evaporation and a less-green landscape.

There is another problem with plants - they work best in a particular climate. For human-bred crops, it is relatively easy for the seed distributors to deliver warm-climate strains to areas that were previously cooler climates.

However, many native plants have a more limited range of seed dispersal, so they often get isolated on cooler mountains within their existing range, and get exterminated when they reach the top of the mountain. Alexander van Humboldt explored some high mountains, and we can now compare his scientific records with the distribution of species today, and we can see them climbing higher.

Native forests and native staple crops can't migrate so readily, and are likely to be overrun by invasive weeds.
 

Offline Tim the Plumber

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Re: Does climate change mean a greener Earth?
« Reply #2 on: 22/05/2016 09:56:03 »
If you live in Siberia or northern Canada, a warmer Earth would result in a greener landscape.

However, if you live on the edge of a desert - in China, Africa, USA or Australia, a warmer climate means more evaporation and a less-green landscape.

There is another problem with plants - they work best in a particular climate. For human-bred crops, it is relatively easy for the seed distributors to deliver warm-climate strains to areas that were previously cooler climates.

However, many native plants have a more limited range of seed dispersal, so they often get isolated on cooler mountains within their existing range, and get exterminated when they reach the top of the mountain. Alexander van Humboldt explored some high mountains, and we can now compare his scientific records with the distribution of species today, and we can see them climbing higher.

Native forests and native staple crops can't migrate so readily, and are likely to be overrun by invasive weeds.

http://www.smh.com.au/environment/climate-change/how-australias-big-wet-befuddled-scientists-20130820-2s8k5.html

Quote
For an 18-month period beginning in 2010, the oceans mysteriously dropped by about 7 millimetres, more than offsetting the annual rise, the US National Science Foundation said in a statement

My personal guessinate, based on the historical situation when it was warmer in the bronze age, is for the present deserts to absorb about 50cm of water as they become the fertile grasslands they once were.

A warmer earth is a wetter earth.

 

Offline evan_au

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Re: Does climate change mean a greener Earth?
« Reply #3 on: 22/05/2016 23:10:36 »
Quote from: Tim the Plumber
A warmer earth is a wetter earth.
Higher temperatures do mean more evaporation from oceans & lakes - but also more thunderstorms, and hurricanes/tornadoes, blizzards, floods and erosion. Climatologists expect this more energetic atmosphere to produce "more extreme" weather.

Higher temperatures also mean faster evaporation from the land, which can turn grasslands into desert.

Quote
as they become the fertile grasslands they once were
There is evidence that where there is now desert, Australia was once covered by a forest populated by megafauna.

I fear that, like many other locations on Earth, once humans arrived, any previously stable ecosystem was destroyed, resulting in deforestation and desertification.

Since humans bought rabbits to Australia (in the past 200 years), it is likely to stay as a desert for a considerable time.

Higher temperatures are also a concern for crop scientists, trying to work out how to produce more food for Earth's growing population. Many of the world's staple grains use C3 metabolism (because it uses a 3-carbon initial step), which becomes less efficient at higher temperatures. Some genetic engineers are thinking about how to make the wholesale genetic changes required to turn C3 crops like wheat into C4 crops like maize (using a 4-carbon initial step).

Many grasses are C3.
« Last Edit: 22/05/2016 23:25:39 by evan_au »
 

Offline puppypower

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Re: Does climate change mean a greener Earth?
« Reply #4 on: 24/05/2016 13:08:07 »
I can see extreme weather in the short term, but this will moderate in the longer term. For example, the polar ice caps set up thermal gradients with the equators which drives ocean currents. Say the poles got warmer, these gradient will go down and slow and alter the currents. The transition will create a wild card, but then things will smooth out when the new patterns appear.

The same is true of vegetation. Some natural things may not make the cut. Manmade crops will have selective advantage, because we will engineer these crops to survive and thrive; necessity is the mother of invention.

More water in the atmosphere means more fresh drinking water. Like the crops, we will figure out how to get this water into play; piped. Once that happens, then things look very bright.
 

Offline agyejy

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Re: Does climate change mean a greener Earth?
« Reply #5 on: 24/05/2016 17:52:23 »
I can see extreme weather in the short term, but this will moderate in the longer term. For example, the polar ice caps set up thermal gradients with the equators which drives ocean currents. Say the poles got warmer, these gradient will go down and slow and alter the currents. The transition will create a wild card, but then things will smooth out when the new patterns appear.

Yeah because it is an awesome idea to mess with ocean currents that are responsible for bringing nutrient rich waters to the surface from the deep sea so that marine life can flourish. It also has a not entirely understood impact on the climate of much of northern Europe. We aren't 100% certain about the exact magnitude of the effect but it does provide about 1 PW of heating to the northern Atlantic near Europe and that part of Europe is much warmer than other places at the same latitude. Removing that rather large source of heat would clearly be pretty disastrous for a large chunk of Europe. For example, the UK and France are roughly as far north as Maine in the US but have a climate more comparable to states much farther to the south.

http://www.pik-potsdam.de/~stefan/thc_fact_sheet.html <- Some facts about the Thermohaline Ocean Circulation
 

Offline Tim the Plumber

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Re: Does climate change mean a greener Earth?
« Reply #6 on: 28/05/2016 10:26:59 »
Quote from: Tim the Plumber
A warmer earth is a wetter earth.
Higher temperatures do mean more evaporation from oceans & lakes - but also more thunderstorms, and hurricanes/tornadoes, blizzards, floods and erosion. Climatologists expect this more energetic atmosphere to produce "more extreme" weather.

The models which predict this are the same ones which have failed to predict the lack of warming since 1998. The climate of the past couple of decades has been exceptionally calm with fewer than expected such extreme events. I think I will not worry about such doom mongering.

Quote
Higher temperatures also mean faster evaporation from the land, which can turn grasslands into desert.

You think that the equitorial zone where average temperatures and evaporation are highest are generally deserts?

Quote
Quote
as they become the fertile grasslands they once were
There is evidence that where there is now desert, Australia was once covered by a forest populated by megafauna.

I fear that, like many other locations on Earth, once humans arrived, any previously stable ecosystem was destroyed, resulting in deforestation and desertification.

Since humans bought rabbits to Australia (in the past 200 years), it is likely to stay as a desert for a considerable time.

Higher temperatures are also a concern for crop scientists, trying to work out how to produce more food for Earth's growing population. Many of the world's staple grains use C3 metabolism (because it uses a 3-carbon initial step), which becomes less efficient at higher temperatures. Some genetic engineers are thinking about how to make the wholesale genetic changes required to turn C3 crops like wheat into C4 crops like maize (using a 4-carbon initial step).

Many grasses are C3.

Are you suggesting that it is difficult to grow food in hot wet places?

Yes there might be some alteration of particular crops but so what? Besides the great increase in the fertile zones of Canada and Central Aisa would much more than compensate for this.

 

Offline chris

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Re: Does climate change mean a greener Earth?
« Reply #7 on: 28/05/2016 10:28:35 »
A warmer earth is a wetter earth.

Maybe, but how is that water distributed? Fairly and everywhere, or contentrated in a few very wet spots?
 

Online tkadm30

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Re: Does climate change mean a greener Earth?
« Reply #8 on: 28/05/2016 11:13:36 »
Assuming anthropogenic climate change decrease solar radiation through the systematic injection of sulfate aerosols in the atmosphere, I guess this could negatively affect plants growth requiring a warm climate for photosynthesis and CO2 sequestration.
 

Offline Tim the Plumber

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Re: Does climate change mean a greener Earth?
« Reply #9 on: 05/06/2016 15:22:00 »
More good news;

Quote
The results of this study thus bode well for the future of rice production in India during the dry season. As the CO2 concentration of the air rises, yields will increase.  And if the temperature rises as models project, yields will still increase, though by not quite as much. These findings, coupled with the fact that the grain nutritional quality (as defined by an increase in amylose content) was enhanced by elevated CO2, suggest there is a bright future in store for rice in a carbon dioxide-enhanced atmosphere.

http://www.cato.org/blog/elevated-co2-temperature-enhance-grain-yield-quality-rice

In there somewhere it says that there is an increased yeald of 22% as well.
 

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Re: Does climate change mean a greener Earth?
« Reply #9 on: 05/06/2016 15:22:00 »

 

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