Anthropogenic Climate Change Exists
Correlation plus a theory is not proof CO2 dominates climate My opponent noted temperature
generally rising since 1900 and CO2 rising since 1900, and claims that because CO2
is a greenhouse gas, it must be responsible for the rise. The error in that logic
is that we do not know how much of the rise is due to CO2 and how much is due to other
factors affecting climate. We could plot increasing consumption of charcoal in backyard
barbecues, noted that burning charcoal heats the atmosphere, and then concluded that
barbecuing causes global warming. The barbecue theory is defeated by showing that
there isn't enough heat generated by the volume of charcoal consumed to have a significant
warming effect. Similarly, Pro offers no analysis that shows CO2 to be even a significant
cause. Pro has the burden to prove not only that CO2 dominated climate in the last
century, but that it will dominate the next century despite all unknown factors affecting
climate. Here is a reconstruction of CO2 and climate over the past 650 million years.
[1. http://www.geocraft.com...] http://www.debate.org... Over geological time, clearly
climate has been dominated by factors other than CO2. On the geological time scale, we are
currently in an unusual period of low temperatures and low CO2. It a very complicated
picture, proving that climate is far more than just CO2. Pro shows the CO2 data for the past 650,000 years.Temperature
follows the same pattern, only CO2 follows temperature. The graphs are here [2. http://www.geocraft.com...]
If the graphs are time aligned, the result is not that CO2 causes warming. Quite the
opposite, CO2 rises about 800 years after temperature rises. Warming causes CO2 because
warmer oceans cannot dissolve as much CO2. In 2013 the prestigious journal Nature
published an up to date scientific reconstruction of climate for the past 2050 years. [3. http://www.nature.com...] It shows that over the period
climate varied by about as much as the present warming, with both the Roman Period and the
Medieval Warm Period warmer. It remains possible that CO2 is contributing significantly
to current warming, but the natural variations are so large that CO2 might be inconsequential.
Current climate science has no explanation for the major climate variations of the past 2000 years. That's why the discredited global warming hockey
stick attempted to prove there were no past variations. Pro has the burden to prove
CO2 dominates. I say it's unlikely CO2 dominates, but no one really knows. http://www.debate.org... Total sea ice is at record levels and CO2 can't explain
why Pro argues that arctic ice is melting, that proves CO2 is the cause. Historically,
Arctic ice melts when Antarctic ice increases in a cycle of 40 to 60 years called
the Pacific Decadal Oscillation (PDO). The PDO pattern fits the cooling period from
the 40s to the 70s that CO2 cannot explain. [4. http://www.drroyspencer.com...] The
Arctic was last clear around 1940. Global warming alarmist scientists warned that
this time the Antarctic was melting as well, and they made the confident prediction
in 2010 was that the Antarctic would be ice free by 2013. What actually happened is
that the Antarctic reached record high levels of ice: “The Antarctic surge is so big
that overall, although Arctic ice has decreased, the frozen area around both poles
is one million square kilometres more than the long-term average.” [5. http://www.dailymail.co.uk...]
If CO2 warming dominates climate, it cannot be that it is overwhelmed by other factors like the PDO. But it is. CO2
theory cannot explain the pause in warming To accurately predict future climate, computer models must be proved to be reliable. We know the models did not predict
ice formation in the Antarctic nor pre-1900 climate variations. In addition, global warming has essentially ceased since 1997, [6. http://wattsupwiththat.com...]
so a check on the accuracy of climate models is how well this pause is predicted. Sscientists predicting CO2 crisis use
many variations of computer models. The collections are called CMIP3 and CMIP5, with
CMIP5 the very latest. ... Climate models cannot simulate past surface temperatures, precipitation or sea ice area.
Those are basic components of Earth’s climate. … The concern about the latest slowdown in warming was addressed by a recent scientific
study by Von Storch, et al. (2013) “ Can Climate Models Explain the Recent Stagnation in Global Warming? ” The one-word answer to
the title question of their paper is, “No”. They stated: However, for the 15-year
trend interval corresponding to the latest observation period 1998-2012, only 2% of
the 62 CMIP5 and less than 1% of the 189 CMIP3 trend computations are as low as or
lower than the observed trend. Applying the standard 5% statistical critical value,
we conclude that the model projections are inconsistent with the recent observed global
warming over the period 1998- 2012. [7. Tisdale, Bob (2013-09-23). Climate Models Fail (Kindle Locations 276-291)] The Von Storch paper is available free in
draft format [8. http://www.mpimet.mpg.de...] There are a number of ocean oscillations
in addition to the PDO. These are not accurately modelled in the computer simulations
and likely account for the rapid warming before the current pause. The Medieval Warm
Period and the following Little Ice Age correlate extremely well with sunspot activity,
but no physical cause of the warming and cooling has been definitively linked to sunspots
so there is nothing in the computer models representing the effects. It is not direct
change in the solar radiation, because that varies too little to explain the large effect.
Danish scientist Svensmark has proposed that changes in cosmic rays linked to variations
in sunspots affect cloud cover by a cloud seeding mechanism, but CO2 scientists discount
that, so nothing is in the computer models. [9. http://wattsupwiththat.com...] All
of the climate change in the past century could be accounted for by less than a 3% change in cloud cover, but even with satellites cloud cover measurement is difficult. The
cloud height is important as well as the density. We don't know future CO2 levels
Everyone, crisis advocates and skeptics alike, agrees that whatever the CO2 sensitivity
it is logarithmic. So if doubling CO2 produces a one degree rise, which is about the
theoretical rise if there is nothing in the climate that magnifies the effect, then doubling it again would produce another degree of
warming. An exponential rise in CO2 produces a linear rise in temperature. If we had
a perfect model of CO2 effects on climate, we would still need to know how much CO2 is left to be produced and at what rate.
Everyone agrees oil and coal are running out, but no one is sure how fast. But as
supplies get scarce, prices rise and alternatives become economically viable. A technological
breakthrough like a cheap, efficient battery would drop carbon consumption dramatically.
It's another major unknown. A clarification of the resolution was agreed to in the
debate comments so Pro must show that CO2 dominates climate in the past and future century. Pro has not made a convincing case that CO2 accounts
for past climate change, nor that either computer models or carbon consumption assumptions are reliable enough
to predict the future. He has the burden of proof.
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