Tag Archives: climate change science

Link
Original ArticleBulletin of Mathematical BiologyDecember 2015, Volume 77, Issue 12, pp 2325-2353

First online: 25 November 2015

  • Yadigar Sekerci
  • , Sergei Petrovskii 

Abstract

Ocean dynamics is known to have a strong effect on the global climate change and on the composition of the atmosphere. In particular, it is estimated that about 70 % of the atmospheric oxygen is produced in the oceans due to the photosynthetic activity of phytoplankton. However, the rate of oxygen production depends on water temperature and hence can be affected by the global warming. In this paper, we address this issue theoretically by considering a model of a coupled plankton–oxygen dynamics where the rate of oxygen production slowly changes with time to account for the ocean warming. We show that a sustainable oxygen production is only possible in an intermediate range of the production rate. If, in the course of time, the oxygen production rate becomes too low or too high, the system’s dynamics changes abruptly, resulting in the oxygen depletion and plankton extinction. Our results indicate that the depletion of atmospheric oxygen on global scale (which, if happens, obviously can kill most of life on Earth) is another possible catastrophic consequence of the global warming, a global ecological disaster that has been overlooked.

Keywords

Phytoplankton Global warming Oxygen depletion Extinction Pattern formation

Advertisements

Scientists at the Large Hadron Collider may have just discovered a new fundamental particle that could change the way we look at the universe. Is this Dark Energy? A giant Neutrino? The big brother of the Higgs Boson? Or could it be the mysterious Graviton?

Global warming calculation

Why Global Warming Will Cross a Dangerous Threshold in 2036

Emitting carbon dioxide at current rates will soon push Earth’s temperature up by 2 degrees Celsius. Here’s how to make the calculation yourself

You can try this exercise yourself. The text below explains the variables and steps involved. You can download the climate data here and the model code here. And you can compare your results with mine, which are here. You can also change the variables to see what other future scenarios are possible. One note: the model runs on MatLab software, which can be obtained here.

Matlab source code for the energy balance model, data used in the calculations and the simulation results discussed in the Scientific American article are available at: www.meteo.psu.edu/holocene/public_html/supplements/EBMProjections

general circulation model (GCM)

A general circulation model (GCM), a type of climate model, is a mathematical model of the general circulation of a planetary atmosphere or ocean and based on the Navier–Stokes equations on a rotating sphere with thermodynamic terms for various energy sources (radiation, latent heat). These equations are the basis for complex computer programs commonly used for simulating the atmosphere or ocean of the Earth. Atmospheric and oceanic GCMs (AGCM and OGCM) are key components of global climate models along with sea ice and land-surface components. GCMs and global climate models are widely applied for weather forecasting, understanding the climate, and projecting climate change. Versions designed for decade to century time scale climate applications were originally created by Syukuro Manabe and Kirk Bryan at the Geophysical Fluid Dynamics Laboratory in Princeton, New Jersey.[2] These computationally intensive numerical models are based on the integration of a variety of fluid dynamical, chemical, and sometimes biological equations.

the changing thermal structure of the atmosphere

Human and natural influences on the changing thermal structure of the atmosphere

Observational satellite data and the model-predicted response to human influence have a common latitude/altitude pattern of atmospheric temperature change. The key features of this pattern are global-scale tropospheric warming and stratospheric cooling over the 34-y satellite temperature record. We show that current climate models are highly unlikely to produce this distinctive signal pattern by internal variability alone, or in response to naturally forced changes in solar output and volcanic aerosol loadings. We detect a “human influence” signal in all cases, even if we test against natural variability estimates with much larger fluctuations in solar and volcanic influences than those observed since 1979. These results highlight the very unusual nature of observed changes in atmospheric temperature.

More IR at the surface

Observational determination of surface radiative forcing by CO2 from 2000 to 2010

Nature
519,
339–343
(19 March 2015)
doi:10.1038/nature14240
Received
09 June 2014
Accepted
15 January 2015
Published online
25 February 2015

The climatic impact of CO2 and other greenhouse gases is usually quantified in terms of radiative forcing1, calculated as the difference between estimates of the Earth’s radiation field from pre-industrial and present-day concentrations of these gases. Radiative transfer models calculate that the increase in CO2 since 1750 corresponds to a global annual-mean radiative forcing at the tropopause of 1.82 ± 0.19 W m−2 (ref. 2). However, despite widespread scientific discussion and modelling of the climate impacts of well-mixed greenhouse gases, there is little direct observational evidence of the radiative impact of increasing atmospheric CO2. Here we present observationally based evidence of clear-sky CO2 surface radiative forcing that is directly attributable to the increase, between 2000 and 2010, of 22 parts per million atmospheric CO2. The time series of this forcing at the two locations—the Southern Great Plains and the North Slope of Alaska—are derived from Atmospheric Emitted Radiance Interferometer spectra3 together with ancillary measurements and thoroughly corroborated radiative transfer calculations4. The time series both show statistically significant trends of 0.2 W m−2 per decade (with respective uncertainties of ±0.06 W m−2 per decade and ±0.07 W m−2 per decade) and have seasonal ranges of 0.1–0.2 W m−2. This is approximately ten per cent of the trend in downwelling longwave radiation5, 6, 7. These results confirm theoretical predictions of the atmospheric greenhouse effect due to anthropogenic emissions, and provide empirical evidence of how rising CO2 levels, mediated by temporal variations due to photosynthesis and respiration, are affecting the surface energy balance.

The Pause

Let’s be clear: The planet is still getting hotter. The so-called pause, or hiatus, in global warming means the rate of temperature rise has slowed. The average global temperature is still going up, but in the past 10 to 15 years it hasn’t been going up as quickly as it was in the decades before.

Although the ongoing increase is trouble, a slower rate is preferable. The question is: Why did the slowdown occur—and how long will it last?

Separate work by Mann, presented in Scientific American article he wrote last April, also indicates that the pause will not last long. Mann calculated that if the world continues to burn fossil fuels at the current rate, global warming would rise to two degrees Celsius by 2036 (compared with preindustrial levels), crossing a threshold that would harm human civilization. And even if the pause persists for longer than expected, the world would cross the line in 2046. The article includes a monumental graph showing all the details. Mann also published the data sources and formula he used, on Scientific American’s Web site, so anyone could replicate his calculations.

Atlantic and Pacific multidecadal oscillations and Northern Hemisphere temperatures

  1. Byron A. Steinman1,*,
  2. Michael E. Mann2,
  3. Sonya K. Miller2

+ Author Affiliations


  1. 1Large Lakes Observatory and Department of Earth and Environmental Sciences, University of Minnesota Duluth, Duluth, MN, USA.

  2. 2Department of Meteorology and Earth and Environmental Systems Institute, Pennsylvania State University, University Park, PA, USA.
  1. *Corresponding author. E-mail: bsteinma@d.umn.edu

The recent slowdown in global warming has brought into question the reliability of climate model projections of future temperature change and has led to a vigorous debate over whether this slowdown is the result of naturally occurring, internal variability or forcing external to Earth’s climate system. To address these issues, we applied a semi-empirical approach that combines climate observations and model simulations to estimate Atlantic- and Pacific-based internal multidecadal variability (termed “AMO” and “PMO,” respectively). Using this method, the AMO and PMO are found to explain a large proportion of internal variability in Northern Hemisphere mean temperatures. Competition between a modest positive peak in the AMO and a substantially negative-trending PMO are seen to produce a slowdown or “false pause” in warming of the past decade.

Climate Oscillations and the Global Warming Faux Pause

Filed under:

No, climate change is not experiencing a hiatus. No, there is not currently a “pause” in global warming.

Despite widespread such claims in contrarian circles, human-caused warming of the globe proceeds unabated. Indeed, the most recent year (2014) was likely the warmest year on record.

It is true that Earth’s surface warmed a bit less than models predicted it to over the past decade-and-a-half or so. This doesn’t mean that the models are flawed. Instead, it points to a discrepancy that likely arose from a combination of three main factors (see the discussion my piece last year in Scientific American). These factors include the likely underestimation of the actual warming that has occurred, due to gaps in the observational data. Secondly, scientists have failed to include in model simulations some natural factors (low-level but persistent volcanic eruptions and a small dip in solar output) that had a slight cooling influence on Earth’s climate. Finally, there is the possibility that internal, natural oscillations in temperature may have masked some surface warming in recent decades, much as an outbreak of Arctic air can mask the seasonal warming of spring during a late season cold snap. One could call it a global warming “speed bump”. In fact, I have.

Some have argued that these oscillations contributed substantially to the warming of the globe in recent decades. In an article my colleagues Byron Steinman, Sonya Miller and I have in the latest issue of Science magazine, we show that internal climate variability instead partially offset global warming.

– See more at: http://www.realclimate.org/index.php/archives/2015/02/climate-oscillations-and-the-global-warming-faux-pause/#sthash.2F7mdCFk.dpuf