Earth surface temperature, trends

Fig. 4. Projected trend of the Earth surface temperature increase. Upper curve, pessimistic scenario with no emission curtailment lower curve, optimistic scenario with significant emission curtailment middle curve, in-between scenario. (Adapted from IPCC 2001.)...

Fig. 1.1 Trends in the temperature at the earth surface as a function of ages. The greenhouse effect [2],...

Paleoclimate information retrieved from marine sediments has been used to reconstruct sea surface temperatures in the western Equatorial Pacific over the past 13,500 y as shown in Figure 25.21. This evidence documents that Earth s temperature has now climbed to a level that has not been seen since 12,000 years ago and is within 1°C of the maximum reached over the past million years. During the past 30 years, the mean surface temperature at this location has been warming at a rate of 0.2°C per decade. This trend is found in most of the other oceans, suggesting that global atmospheric temperatures are now at or near the highest level of the Holocene. 

One of the first comprehensive estimates of global mean, near-surface temperature over the earth s lands and oceans was reported in 1986 (Jones et al, 1986). The data showed a long-timescale warming trend. The three warmest years were 1980, 1981, and 1983, and five of the nine warmest years in the entire 124-year record up to 1984 were found to have occurred after 1978. It was apparent from this study that over this period, annual mean temperature increased by about 0.6 to 0.7°C, and that about 40 to 50% of this increase occurred since about 1975. According to many analysts, the warmest year on record up to 1995 is 1995, and recent years have been the warmest since 1860 despite the cooling effect of the volcanic eruption of Mt. Pinatubo in 1991... 

Before the twenty-first century, what was the trend (the dotted line in diagram b) for Earth s average surface temperature What does this trend predict for the average surface temperature in the year 2000 ... 

The observed trends in the NAM towards higher indices may have resulted from human-induced changes in the temperature structure of the lower stratosphere in response to greenhouse gas emissions and ozone depletion (Shindell et al., 2001). The radiative effects of solar activity and of volcanic eruptions may also have produced NAM- like signatures detectable at the Earth s surface. The response of the Earth system to climate forcing may therefore involve changes in particular dynamical modes, and hence the human influence on climate at the Earth surface may occur in part by way of the stratosphere. 

The variations in regional surface temperatures for the last 18,000 years are shown in Figure 23.2. In Figure 23.2, we see that the MWP and the LIA are little more than ripples on the longer and more significant warming trend of 4—5°C of the last 15,000 years, which marks the recovery of the Earth from the Ice Age. The present warm epoch, beginning... 

FIGURE 23.8 Trends in natural and human influences relevant to Earth s climate during the past four centuries (Lean and Rind 1996). Compared are annual averages of (a) estimates of the solar total radiation, from Figure 23.7c (b) variations in the amount of volcanic aerosols derived from an index (global dust veil index) of known eruptions and (c) the concentration of C02 in the atmosphere. The decade-averaged estimate of the Earth s surface temperature, shown in (d), combines continuous instrumental records from the most recent 150 years with a less certain reconstruction based on various climatic indicators. 

FIGURE 6.5 Trends in Earth s surface temperature over the past 1000 years and a more detailed analysis of the temperature trend near Earth s surface over the past 140 years. A more detailed presentation of this data may be found at http //www.ipcc.ch/present/graphics/2001syr/large.0516jpg. 

FIGURE 8.3 Global surface temperature variations compared to the 1960-1990 average as measured at Earth s surface indicating an upward trend since 1975. (Data from U.S. National Oceanic and Atmospheric Administration National Climatic Data Center, http //www.ncdc.noaa.gov/sotc/global.)... 

The temperature of the surface of the Earth is rising about 0.10-0.15°C per decade (see graph). If current trends in population growth and energy use continue, by the middle of the twenty-first century the concentration of CO, in the atmosphere will be about twice its value prior to the Industrial Revolution. What are the likely consequences of this doubling of the CO, concentration ... 

Baba and Endou 117) reported that CaO is an active catalyst for isomerization of VBH to EBH when it is evacuated at temperatures above 800 K, whereas MgO did not show any activity for this process. However, some discrepancies have been reported by Kabashima et al. 10), who found that MgO, CaO, SrO, and BaO catalyze the isomerization of VBH to EBH, with the order of activity being CaO > MgO > SrO > BaO. This order in activity is attributed to the trends in base strength of oxides (BaO > SrO > CaO > MgO) and the surface area, the latter decreasing in the order MgO > CaO > SrO > BaO (Table II). The activity of the CaO was the highest among these alkaline earth metal oxides, and the activity of the MgO varied with the pre-treatment temperature, reaching a maximum it was 873 K ... 

Figure 4b. Area-normalized display of data from Figure 4a. The regression line of temperature versus latitude for the IAEA data of Fiicke and O Neil (1999) was used to assign to each site an equivalent latitude corresponding to its temperature, with points plotting beyond 90° assigned to 90°. Precipitation 5 0 ratios are plotted against the fraction of the Earth s surface poleward of this equivalent latitude. This emphasizes that the systematic variation of the 5 0 of precipitation with temperature is small compared to the variability about that trend for most of the Earth s surface. The equivalent temperature shown along the top is the temperature corresponding to the equivalent latitude of the regression line.

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