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It is well known that the diversity of life appears to fluctuate during the course of the Phanerozoic, the eon during which hard shells and skeletons left abundant fossils (0-542 million years ago). Here we show, using Sepkoski's compendium of the first and last stratigraphic appearances of 36,380 marine genera, a strong 62 +/- 3-million-year cycle, which(More)
We report an estimate of the Earth's average land surface temperature for the period 1753 to 2011. To address issues of potential station selection bias, we used a larger sampling of stations than had prior studies. For the period post 1880, our estimate is similar to those previously reported by other groups, although we report smaller uncertainties. The(More)
China has recently made available hourly air pollution data from over 1500 sites, including airborne particulate matter (PM), SO2, NO2, and O3. We apply Kriging interpolation to four months of data to derive pollution maps for eastern China. Consistent with prior findings, the greatest pollution occurs in the east, but significant levels are widespread(More)
and political issues increasingly have a strong high-tech content. Misjudge the science, make a wrong decision. Yet many of our leaders never studied physics and do not understand science and technology. does not require physics. Physics for Future Presidents (PffP) is a course designed to address that problem. Physics is the liberal arts of high(More)
By considering radioisotope dating as a problem in trace element detection, and by using the cyclotron as a high-energy mass spectrometer for this purpose, we have shown that one can greatly increase the maximum age that can be determined while simultaneously reducing the size of the sample required. The cyclotron can be used to detect atoms or simple(More)
A new mathematical framework is presented for producing maps and large-scale averages of temperature changes from weather station data for the purposes of climate analysis. This allows one to include short and discontinuous temperature records, so that nearly all temperature data can be used. The framework contains a weighting process that assesses the(More)
22 23 We report an estimate of the Earth's average land surface temperature for the period 24 1753 to 2011. To address issues of potential station selection bias, we used larger 25 sampling of stations than had prior studies. For the period post 1880, our estimate is 26 similar to those previously reported by other groups, although we report smaller error(More)
An analysis team led by Anthony Watts has shown that 70% of the USHCN temperature stations are ranked in NOAA classification 4 or 5, indicating a temperature uncertainties greater than 2C or 5C, respectively. This uncertainty is large compared to the analyses of global warming, which estimate the warming of 0.64 ± 0.13 C over the period 1956 to 2005. The(More)