Global warming

(Upload on May 27 2022) [ 日本語 | English ]

Global warming (地球温暖化)

Mount Usu / Sarobetsu post-mined peatland
From left: Crater basin in 1986 and 2006. Cottongrass / Daylily

HOME > Lecture catalog / Research summary > Glossary > Global warming

Greenhouse effect (温室効果)

Thermal radiation from a planetary surface is absorbed and re-radiated by atmospheric greenhouse gases represented by CO2

Temperature

electromagnetic spectrum (電磁スペクトル), climate (気候)
A physical property of a system that underlies the common notions of hot and cold

absolute temperature
centigrade temperature (degrees C, 摂氏)
Fahrenheit temperature (degrees F, 華氏) → unit transformation (単位換算)
Kelvin temperature

→ cherry blossom front (桜前線)

Concerened with seed germination (種子発芽) (Black et al. 2006) and seed dormancy (種子休眠)
Cumulative temperature above a base temperature below which plant development (or germination) ceases, and is often calculated on a daily basis, as follows.

T_t (°C d) = Σ(((T_max - T_min)/2) - T_b)

[ warming experiment | methane ]

where T_max and T_min are the daily maximum and minimum temperatures and T_b is the base temperature.
Data are plotted as the reciprocal of the duration (in days) to x% germination against the mean temperature (T). The inverse of duration (1 d^-1) represents the development rate (D_R). Least squares regression analysis was used for the positive linear portion of the response whereby:

D_R = a₁ + b₁T
T_b = -a₁/b₁
and
T_t = 1/b₁

Warming experiment (温暖化実験)

To demonstrate the effects of climate chages on plants in fields, the following field experiments are important.

Types of experiments

Table 1a. Comparison of currently used methods for experimental warming of terrestrial ecosystems (Shaver et al. 2000)

Method	Mechanisms of warming	Advantage	Disadvantage
Field greenhouse	"Greenhouse warming" (i.e., reflection of reradiated infrared energy and reduced advective energy loss)	Simple and inexpensive; requires no electrical power	Little or no temperature control and large temperature variability; other artifacts include altered light, wind, humidity, and precipitation regimes
Passive open-top chamber (OTC)	Same as above	Same as above	Little or no temperature control; altered wind and humidity; only small areas can be manipulated uniformly
Active open-top chamber (OTC)	Same as above plus warming by advection of electrically heated, forced warm air	Precise control of air temperature difference; may be combined with CO₂ control	Altered wind regime, humidity, and evapotranspiration
Active soil warming	Warming by conduction from buried electrical resistance cables	Precise control of soil temperature difference; may be combined with greenhouses or OTCs	Altered soil moisture regime; no effect on aboveground temperatures
Electric infrared heat	Warming by increased infrared radiation	Precise control of energy input; direct simulation of global change in energy balance	Warming depends entirely on radiation; no change in advective energy inputs
Reciprocal or one-way transplantation	Transplantation of plants, soils, or whole plant?soil systems to warmer or cooler locations	Comparison of relatively natural temperature gradients	Disturbance effects; multiple environmental changes make it difficult to assign specific causes to responses observed

[1] Greenhouse and shaded house for monitoring the effects of climate chagne for long-term at Toolik Research Station on August 8 2009 (68°38'N, 149°36'W). [2] an open-top chamber established at Abisko Scientific Research Station, Abisko, Sweden on September 24 2000 (Photo by Wada N.)

→ Ecology and global warming (地球温暖化生態学特論), references

Methane (メタン)

Methane is the one of the major global-warming gas. Global Warnming Potential (GWP) is 21 (or 23).
→ wetland (湿原)

Methane emissions

Methane flux and vegetation types in grassy marshlands near Kolyma River, northern Siberia

Table 2. Mean values with standard error of each environmental factor in each cluster group. The different letters upper-right the mean values indicate significantly different at P < 0.01 (Tukey's HSD test). Except for the measurement of pH, EC, Eh and thaw depth in cluster group 1 where we did not measure in four plots, sample numbers are coincidence with number of plots clustered by TWINSPAN (Table 1). On water depth, minus value indicates the depth of soil where the ground water appeared. (Tsuyuzaki et al. 2001)

It may be possible that terrestial plants emit methane under aerobic conditions that has not been mentioned (Keppler et al. 2006).
Methane formation driven by reactive oxygen species across all living organisms (Ernst et al. 2022)

Fig. 1. Proposed mechanism of ROS-driven CH₄ formation in living systems. CH₄ formation from methyl radicals, which are produced in cells by ROS and ferrous iron. Metabolically active cells generate H₂O₂ and import and reduce ferric iron, thereby fuelling the Fenton chemistry that drives methyl radical formation from metabolites containing sulfur- and/or nitrogen-bonded methyl groups. Conditions that affect cellular levels of ROS, ferrous iron and external supply or cellular production of methyl donor substrates modulate CH₄ formation.

Table 1. Methane flux and vegetation types in grassy marshlands near Kolyma River, northern Siberia (Tsuyuzaki et al. 2001)
Grassland type	Eriophorum grassland	Horsetail grassland	Carex grassland	All plots
Water depth (cm)	-5.1 ± 0.8a	5.2 ± 0.3b	5.4 ± 0.5b	2.90 ± 0.6
pH	5.75 ± 0.04a	6.15 ± 0.03b	6.25 ± 0.01c	6.08 ± 0.03
Air temperature (°C)	18.8 ± 0.9	17.0 ± 1.0	17.4 ± 0.3	17.5 ± 0.6
EC (mS/m)	5.20 ± 0.29a	8.86 ± 0.30b	6.61 ± 0.13c	7.64 ± 0.26
Eh (mV)	451.4 ± 7.8a	455.7 ± 2.0a	454.9 ± 1.2a	454.6 ± 2.2
Soil humidity (%)	49.8 ± 2.3a	63.8 ± 1.4b	55.5 ± 1.0a	58.6 ± 1.2
Thaw depth (cm)	39.7 ± 0.8a	69.4 ± 3.2b	59.4 ± 0.4b	59.8 ± 2.5
Elevation difference (cm)	7.6 ± 0.8a	10.1 ± 0.4a	14.7 ± 0.9b	10.2 ± 0.4
Methane flux (mg CH₄/m²/d)	-1.9 ± 1.6a	165.5 ± 6.8b	73.2 ± 4.9c	105.1 ± 9.5

Scenario (シナリオ)

SRES

= special report on emissions scenarios