Weather and Climate Change Blog

From all indications there will be no functionally effective, multinational agreement to radically and precipitously ratchet down carbon emissions any time soon. Anything less than that just won’t do.

So we will be at the mercy of how rapidly the free market and government controlled economies can produce, export and scale up clean, renewables to global usage, Anything less than something like 80% of global emission at the 1990 level will not suffice. The reason for that is CO2 concentration/rate of accumulation is already well past the point where at least 2C of warming will occur relative to pre-industrial times when CO2 hadn’t exceeded 280ppm. It is now over 390ppm and rising at a rate of 2ppm per annum.

It’s been at least 3 million years since CO2 levels exceeded 400ppm and temperature was as warm as we stand to soon experience. Atmospheric CO2 of over 400ppm coincided with global temps 4-6C warmer than today going back 20 million years ago. Since the mid Cretaceous Period about 100 million years ago when CO2 hovered around 600ppm and global temps were as much as 10C warmer than today, CO2 has experienced a general decline in the atmosphere to reside generally between 180ppm and 280ppm over the past 3 million years of northern hemisphere periodic glaciation.

Natural geologic process regulate the amount of CO2 resident in the atmosphere on multi-million year time frames. Once in the atmosphere CO2 level acts to regulate surface temperature on Earth much the same way as a thermostat does. How it finds itself into the atmosphere in the first place is dependent on the ambient temperate and how this affects the chemistry of rock weathering and CO2 concentration within the oceans. Warmer seas hold less CO2 in solution, so the warmer it becomes due to an enhanced rate of rock weathering, the less capable the oceans are of scrubbing that CO2 out of the atmosphere. The added CO2 then acts to enhance the greenhouse effect. Atmospheric CO2 acts therefore as both a feedback to warming and also a cause of warming. This is a classic positive feeback loop.

Now mankind comes along and becomes a source for introducing CO2 to the atmosphere at a much greater rate than what occurs by the process of natural rock weathering. Natural CO2 sinks were in balance with natural sources of CO2 given overall conditions. Humans are now responsible for about 3% of the total CO2 engaged in the natural carbon cycle as the Earth system literally inhales and exhales CO2. That 3% is the marginal difference which has disrupted the natural balance. The Earth, given current geological conditions, is capable of inhaling only so much, which used to be close to equilibrium with how much it was exhaling. That extra 3% contributed by man’s activities is building in the Earth’s oceans and atmosphere and it will remain there for 100′s to 1,000′s of years, only slowly falling to natural background levels as natural process eventually catch up with the imbalance. The higher that CO2 concentration becomes in parts per million, the longer will be required to reestablish balance over coming decades and centuries.

That basically in a nutshell is what has and is going on according to scientific investigation.

Solar evolution guarantees the Earth will experience surface temperatures hot enough to boil away the oceans. That will produce a run away global warming, but not for at least another 1 billion years. It is estimated that multi-cellular life has reached about the halfway point for viability on Earth,

Also, remember…water vapor mixing ratio follows ambient temperature. Water vapor acts as a powerful greenhouse gas to enhance any warming in an act of positive feedback. This feedback is partially mitigated by the negative lapse rate feedback concurrently induced (reducing greenhouse effect..net positive) and also by changes in cloudiness. Water vapor entering the atmosphere will not by itself cause a run away condition so long as an equal amount continues to precipitates out as what evaporates in.

In the deep past, climates warmer than 10C above current conditions have occurred. The climate system did not run away. Over the next several centuries humans stand to recreate the conditions of the PETM of 55 million years ago. The climate did not run away then either. Regardless of the global warming event we are currently immersed in (and causing), eventually the Earth will return to the climate conditions forced by the dynamic equilibrium between solar radiation and the Earth’s natural production of greenhouses gases.

As it just so happens, atmospheric CO2 content has fallen in step with the warming sun over the past several hundred million years. Good thing too, imagine how warm the Earth would be today if CO2 measured in parts per million were near 800ppm as they were during the period you refer to.

We are really just incredibly lucky to be here in the first place. The Earth just so happens to reside in a narrow region just the right distance from the Sun to sustain temps suitable for life and for water to exist near it’s triple point (gas, liquid, solid). We have a moon which stabilizes the Earth’s tendency to wobble wildly about it’s rotational axis. This is a major reason we have stable seasons on Earth. A few chance big asteroid impacts have randomly shaped the evolution of life on Earth. If any of of these and many more coincidences had not occurred we would most likely not be here. NO, we wouldn’t be here.

One of those chance happenings is that over the past several hundred million years CO2 levels have declined. Tectonic process involving mountain building and the positions of the continents, the amount of water runoff from the continents to the seas. The nature of life itself. The temperature, cooler conditions slowing chemical rock weathering in concert with all the above determine the amount of CO2 in the atmosphere. We are just lucky things have taken place just the exact way they have, including a period of low atmospheric CO2 coinciding with a warming Sun. If that had not been the case, the heat of the Cretaceous Period would have built even higher with the warming of the Sun, and who knows maybe the dinosaurs would have survived the asteroid to remain the predominant form of life on the planet.

Greenland ice melt seen at lower temperatures: study Sun, 11 Mar 2012 15:00:07 -0400
LONDON (Reuters) – The complete melt of the Greenland ice sheet could occur at lower global temperatures than previously thought, a study in the journal Nature Climate Change showed on Sunday, increasing the threat and severity of a rise in sea level.

INDIANA U. (US) — Over the next century, the climate will change more than 100 times faster than the rate at which species can adapt, according to new research.

Snakes struggle to keep pace with climate.

PENN STATE (US) — Engineering our way out of global climate warming may not be as easy as simply reducing the incoming solar energy, a research team concludes.

Designing the approach to control both sea level rise and rates of surface air temperature changes requires a balancing act to accommodate the diverging needs of different locations.

Climate conflict: Sea level vs. surface temp.

As hot weather continues to bake much of the county’s midsection, the National Weather Service issued heat advisories and extreme heat warnings for parts of 15 southern states yesterday. Across states like Texas, Oklahoma, Arkansas, and Mississippi, temperatures set new daily high records, adding to the tally of thousands of temperature records that were broken so far this summer across a wide swatch of the country.

Here are some of the most striking records set during the past week:

On Wednesday, the mercury hit 115°F in Fort Smith, Arkansas, which shattered the all-time record of 107 degrees, set back in 1896. Fayetteville, Ark. hit 110°F on Wednesday, which broke the 47-year-old record of 102°F. Little Rock also set a new all-time record high temperature, at 114°F.

July 2011 was the warmest month on record in Lubbock, Texas. This year, the city has already had at least 34 days with temperatures at or exceeding 100°F, which breaks the previous record of 29 days set during the “Dust Bowl” era. With most of August still to come, this new record will probably end up even higher.

Tyler, Texas hit a record-breaking 36-day streak of triple-digit temperatures on August 2. Dallas-Ft. Worth has had 34 straight days with temperatures above 100°F (the second longest streak for the area).

It was also the hottest July on record in Oklahoma, where the state’s average temperature was 89.1°F. That’s more than seven degrees above average for July, and 1°F warmer than the previous record set in 1954.

Most of extreme southwestern Oklahoma has had 43 consecutive days or more with temperatures above 100°F, and the streak is expected to continue well into August. On average, this region expects 30-40 days above the century mark each year. According to Gary McManus, Oklahoma associate state climatologist, the highest number of 100°F days ever in one year is 86, set in Hollis in 1956:

http://www.climatecentral.org/news/records-fall-during-southern-great-plains-heat-wave/

A doubling of CO2 will produce approximately a radiative forcing of 3.7W/m^2 as measured from the tropopause and a resultant tendency to warm the surface a bit less than 1.2C at equilibrium in a hypothetical situation with zero feedbacks. This follows rather straightforwardly from basic physics.

However, in the real world there will be feedbacks within the climate system in response to that initial 1.2C of warming per doubling of CO2. Cloud and aerosol feedback, water vapor feedback, lapse rate feedback, carbon cycle feedback and ice albedo feedback are the most prominent examples. Some of these give positive feedback, some negative feedback and all to varying degrees of impact. There are very complicated interactions involved which are in some cases not well understood at all. Climate science refers to these feedback processes and interactions as the climate’s sensitivity to an initial perturbation.
Equilibrium climate sensitivity is not an unknown. It is not exactly pinned down to much better than a factor of 3 however. So we have quite a bit of uncertainty involved. There likely is no rock hard figure, each set of particular global configurations probably has its own unique climate sensitivity to an initial warming influence the equal of 1.2C.

However, by assessing past climate change (the past several ice age cycles), volcanic eruptions and yes, computer modeling we have honed in on a most likely range of sensitivity ( 2C – 4.5C).

Here is a paper describing a determination of climate sensitivity which does not involve modeling:

Using NCEP reanalysis data that span four and a half solar cycles, we have obtained the spatial pattern over the globe which best separates the solar-max years from the solar-min years, and established that this coherent global pattern is statistically significant using a Monte-Carlo test. The pattern shows a global warming of the Earth’s surface of about 0.2 °K, with larger warming over the polar regions than over the tropics, and larger over continents than over the oceans. It is also established that the global warming of the surface is related to the 11-year solar cycle, in particular to its TSI, at over 95% confidence level. Since the solar-forcing variability has been measured by satellites, we therefore now know both the forcing and the response (assuming cause and effect). This information is then used to deduce the climate sensitivity. Since the equilibrium response should be larger than the periodic response measured, the periodic solar-cycle response measurements yields a lower bound on the equilibrium climate sensitivity that is equivalent to a global warming of 2.3 °K at doubled CO2. A 95% confidence interval is estimated to be 2.3-4.1 °K. This range is established independent of models.

Climate change threatens global security, warn medical and military leaders.

Here Dr. Joe Romm of Climate Progress interviews two prominent climate scientists.

Joe Romm Interviews Dr. Christopher Field

and then

Dr. Michael MacCracken

The climate change we are concerned with is the consequence of global warming brought about by human activities. As the world warms all the aspects of climate such as average temperature, average humidity, prevailing wind direction, average cloud amount, precipitation type and amount etc. will change at any given location. Global warming represents the averaged global temperature as it increases over time frames measured in decades to centuries.

The basic physics behind AGW began to take shape over a century ago and has progressed mostly since the 1960′s to the state of the science today. To say this science was formulated only since in 80′s and 90′s as some sort of liberal, socialist plot is just wrong .

Everyone should familiarize themselves with this website: The Discovery of Global Warming

Projections of long-term global warming are in the first place rooted in standard physics which informs us that a doubling of CO2 will produce a climate forcing equaling 3.7W/m^2 (watts per square meter). This forcing according to Planck’s Law and the Stephan Boltzmann equation will warm the planet a bit less than 1.2C AT EQUILIBRIUM and before the consideration of feedbacks.

Secondly, the EQUILIBRIUM CLIMATE SENSITIVITY is ESTIMATED to lie somewhere between 2.0C and 4.5C. This factor (involving feedbacks) is figured from the study of past climate’s response to understood forcing, volcanic eruptions and yes computer modeling. Here is where most of the uncertainty resides. That we can pin this down to a net overall climate response to a doubling of CO2 is better than a crude estimate.

If a tipping point is passed, such as the oceans becoming a net source of CO2 rather than a sink, or methane release from melting permafrost in the northern tundra regions takes hold, the effect would be much more significant than that from a mere doubling of CO2. At the rate we are going, we will easily exceed a doubling of CO2 since pre-industrial times by mid to late century. We stand to potentially warm the globe to a level not seen for over 15 million years if we unleash these climate changing forces, and it would occur in just a few centuries rather than over many thousands and millions of years. This would absolutely be uncharted territory for much of today’s life adapted to current conditions, let alone well outside the climate in which humans have evolved and thrived while enabling our population to approach 7 billion worldwide.

That last figure is the biggest problem of them all, it’s not so much what we do as it is how many of us are doing those things.