The critical difference between today's global warming and Earth's previous climate changes is that?

Question

The critical difference between today's global warming and Earth's previous climate changes is that?

Answer 1

There have been dramatic periods of rapid global warming in the past. The last Ice age ended in a matter of decades. The temperature shot up by 9 degrees celcius in just 20 or 30 years. The mega-mammals of the Ice Age died out in a single generation. What caused it? Maybe it was human activity then too. Maybe humans burned off massive swaths of forest filling the air with CO2. This was a common hunting technique in primitive cultures. And we have no idea how many civilizationtions disappeared as coastlines were swallowed up by rising sea levels. But there were rapid warming cycles long before humans ever existed. Maybe it was natural. Maybe it was some dire cataclysm. But one thing the geologic record teaches us is that the planet does not stay stable forever. The Planet responds to changes and the planet goes through natural cyclic changes. Humans have lived through many of these changes before. They are extremely hard, but if we are adaptable we will survive as a species. The difference now is that we have become complacent that the world will not change and think we can control it. So we may be less able to adapt to it unless we get ready for it.

Answer 2

is that the recent recordings have been far greater that recordings in the past.  Carbon readings have grown to levels that are far greater then ever before and climates in certain areas have totally changed leaving areas that had some percipitaion, face total draught and areas that were plush with greens and rivers are now bearin (sp)

Answer 3

the critical difference between today's global warming and Earth's previous climate changes is that...today's global warming is today and previous climate changes happened previously.

Answer 4

...for the first time in Earth's history, a single species is the driving force behind the change.

Answer 5

Gore wasn't around then

Answer 6

We are not currently facing global warming. In fact we are coming to the end of the pleistocene ice ages.

Global warming is bunk. This is just the temperature of our earths age at this point in history.

go to the following geology web site. Or any geology website.

http://www.geocraft.com/WVFossils/ice_ag...

Answer 7

Today's climate change is induced by mankind.

Answer 8

They have yet to prove which is causing warming...water or CO2.Both are interrelated-chicken or the egg philosophy.Actually the concept of GW warming is not a proved concept...just theory.Two Hemisphere's,one heats the other cools, at different rates.

When they have a irrefutable answer I want to know.

Answer 9

It's a whole lot nicer sitting on the beach in shorts than living in an igloo.

We are blessed with this truely great period in time to be living.

Funny thing is the global warming enthusiast claim the warming will not make hot days hotter. It makes cold days warmer and nights warmer. Sounds like paradise for me. How about you?

Answer 10

Throughout history, weather changes have often been used as religious evidence of man's guilt.  The difference is today we can assert that claim with a more accurate measurement of the weather change.

Answer 11

warming trends that typically occurred over millions of years have been condensed into decades and are increasing exponentially.

Answer 12

That today's global warming has left us.

Answer 13

We now measure temperature and have thousands of measurement stations all over the world to determine precise temperatures at given locations.   We have satellites taking atmospheric readings.   We have scientists whose job it is to calculate global average temperatures.

In the past, during warm periods within human history, mankind wasn't even aware that the earth was not flat.   Our record of past warm periods is based upon crop yields, tree lines, severe droughts, archaeological finds in retreating glaciers, plant and animal species thriving where they do not now grow, simple farming occurring at latitudes where it is not now possible with modern machinery.  

The exactness of today's measurement is, I believe, the reason why we think today's shifts are sharper than past shifts.  All the evidence we have of past climates is from long-term patterns and indirect proxy data.

Answer 14

Global Warming is not real.

Answer 15

Today politicians want to tax the climate change.

Answer 16

There weren't people trying to use climate change to gain political power during all the other ones..

Only difference.

Answer 17

Now there is a temperature-independent source of quantities of CO2 too great for the natural carbon cycle to absorb (humans burning fossil fuels).

This difference is observable by the fact that atmospheric CO2 is currently increasing at the same time as global temperature, whereas in the past there was an approximately 800 year lag between the two (with temperature increasing first).  This is because CO2 is less soluble in warmer water, so in the past when the planet warmed (caused by natural variations such as the planet's orbital [Milankovitch] cycles), the oceans began to emit CO2, which in turn increased the global warming, but it took ~800 years for the planet to warm enough to trigger this feedback.

We also know that the atmospheric CO2 is increasing almost entirely due to humans burning fossil fuels by looking at the ratio of carbon isotopes, as discussed here:

http://www.realclimate.org/index.php?p=8...

So putting it all together - we know CO2 is a greenhouse gas, we know greenhouse gases cause warming, we know that for the first time there is a source of CO2 which is emitting the greenhouse gas in large amounts, and we know these emissions are not being caused by the planet warming.

Thus we're seeing exactly what we would expect to see - human fossil fuel emissions causing global warming.

Answer 18

I'd identify two main differences:

1. In the past, massive volcanos were the source of the CO2 emissions, but that is not the case today:

"...according to papers from back in the late 1990s, 'Volcanoes contribute about 110 million tons of carbon dioxide per year while man’s activities contribute about 10 billion tons per year.' This means that anthropogenic CO2 emissions are 100x greater than volcanic CO2 emissions."

http://www.scholarsandrogues.com/2007/07...

2. In past greenhouse gas warmings, mankind was not around to be one of the species that went extinct after a few degrees of warming dramatically altered ecosystems across the planet:

"An even larger amount of carbon dioxide (CO2) would also have been expelled by Traps volcanism. But in contrast to the sulfate aerosols, carbon dioxide remains in the atmosphere for extended periods of time (centuries), though it decreases slowly over that interval. As a greenhouse gas, it warms the atmosphere, changing ecological conditions. (Deccan Traps volcanism, coming before the end of the Cretaceous, is estimated to have warmed the world by 3° to 5°C, or 5.4° to 9°F; Ravizza and Peucker-Ehrenbrink, 2003.) And because it combines chemically to form carbonic acid, it also produces mildly acidic rain. Acid rain can dissolve calcium carbonate shells, particularly those at or near the ocean surface.  Additionally, acid rain leaches vital nutrients from the soil, resulting in plant stunting and death."

http://www.killerinourmidst.com/P-T%20bo...

Climate Model Links Warmer Temperatures to Permian Extinction

http://www.physorg.com/news6003.html

"The implication of our study is that elevated [carbon dioxide] is sufficient to lead to inhospitable conditions for marine life and excessively high temperatures over land would contribute to the demise of terrestrial life," the authors conclude.

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So the fact that there were past CO2-caused warmings can be no consolation to us.  

In fact, the evidence that CO2 was a factor in those warmings and that the past warmings often killed most species on the planet clearly demonstrates that our contribution to rising atmospheric CO2 is not an issue to dismiss lightly.