Simulating atmospheric d13CO2 during the last 740,000 years: Model-based estimates in the context of ice core measurements

The ratio of the stable carbon isotopes of atmospheric CO2 (δ 13 CO2 ) contains valuable information on the processes which are operating on the global carbon cycle. However current δ 13 CO2 ice core records are still limited in both resolution, temporal coverage as well as precision. To make optimal use of the existing and future δ 13 CO2 ice core records an estimate of the expected temporal variability would help to constrain for the acceptable measurement uncertainty and resolution to successfully retrieve the characteristic variability in δ 13 CO2 . In this study we performed simulations with the carbon cycle box model BICYCLE with special emphasis on atmospheric δ 13 CO2, proposing how changes in δ 13 CO2 might have evolved over the last 740,000 years. The overall model dynamic is validated with reconstructions of δ 13 C in benthic foraminifera in thedeep Pacific and with atmospheric CO2 ice core data. On glacial/interglacial timescales lower surface ocean temperature is most important for lower glacial δ 13 CO2 , followed by the release of isotopically lighter terrestrial carbon. In addition, changes in the terrestrial biosphere also dominate deep ocean δ 13 CO2 but have only a limited effect on atmospheric pCO2 . All other oceanic processes lead to higher than present glacial δ 13 CO2 . Taken all processes together the effects nearly cancel each other and there are nearly no glacial/interglacial amplitudes in δ 13 CO2 in line with ice core data. However faster variations of up to 0.3 occur throughout the whole simulation period. Due to our model configuration, terrestrial carbon storage is very sensitive to temperature changes over northern hemispheric lands, which accompany the reorganization of the Atlantic meridional ocean circulation during fast climate fluctuations (Dansgaard/Oeschger events). These fast events intensify the frequency and amplitude in δ 13 CO2 . However, due to ocean uptake of additional carbon as well as the signal attenuation in ice cores, the amplitudes of such events are strongly time scale dependent

Is regulating the solvency of banks counter-productive?

This paper contains a critique of solvency regulation such as imposed on banks by Basel I and II. It argues that banks seeking to maximize rate of return on risk-adjusted capital (RORAC) aim at an optimal level of solvency because on the one hand, solvency S lowers the cost of refinancing; on the other, it ties costly capital. In period 1, exogenous changes in mean returns dµ and in volatility occur, causing optimal adjustments dS * / dµ and dS * / ds in period 2. Since banks reallocate their assets with certain µ and s values in response to the changed solvency level, an endogenous trade-off with slope dµ / ds results in period 3. Both Basel I and II are shown to modify this slope, inducing at least some banks to opt for a higher value of s in certain situations. Therefore, this type of solvency regulation can prove counter-productive

Energy and Climate Policy: USA Continues to Trail behind, Despite Positive Change

In the course of current climate negotiations, the world is watching the United States in particular. Together with China, the U.S. is by far the largest emitter of greenhouse gases. Real progress in protecting the global climate requires substantial action on America's part. The U.S. has the potential to significantly reduce emissions. Per capita energy consumption in the U.S. is still about twice that of Europe. An assessment of current energy and climate policies in America is disillusioning. So far, federal and state measures have had only limited success - both in terms of increasing energy efficiency and in the use of renewable energy. While some regional initiatives are promising - for example, the establishment of renewable portfolio standards, or emissions trading schemes in the Northeast and West of the country - they ultimately lack sufficient ambition and scope. Proposals currently under debate in Congress for a national energy and climate protection law are highly contested, even though they do not set particularly demanding goals for reducing emissions in the medium term. Against this backdrop, the U.S. cannot be expected to catch up anytime soon in the area of climate protection.Climate Policy, Energy Policy, Renewable Energy, USA

The Impact of Euro Introduction on the Vertical Price Transmission in the German Food Market - Does Money Illusion Matter?

In this paper the impact of the introduction of the Euro on the vertical price transmission in German food markets is analyzed. It is hypothesized that following the introduction of the Euro the presence of money illusion might have lead to higher real prices, and if so it is likely accompanied by higher margins between respective wholesale and retail prices. While other studies have mainly focused on the behavior of average prices, here reactions at the individual store level are investigated. For cucumber and carrots the vertical price relationships between retail and wholesale prices are estimated by employing an error correction approach, which is enhanced to test for structural breaks with a flexible time frame using a F-max approach. The results indicate significant changes in the vertical price relationships for one forth of the retailers under study. Though significant the directions of changes do not uniquely fit the theoretical predictions for money illusion. Thus, the majority of German food retailers has not used the introduction of the Euro to increase their mark ups.Financial Economics, Industrial Organization,

DOES MONEY ILLUSION MATTER? THE IMPACT OF EURO ON THE VERTICAL TRANSMISSION OF FOOD PRICE IN GERMANY

In this paper the impact of the introduction of the Euro on the vertical price transmission in German food markets is analyzed. It is hypothesized that the presence of money illusion might have lead to higher real prices as a result of the Euro, and if so it must be accompanied with a higher margin between the respective wholesale and retail price. While generally studies focus on the behavior of average prices, in this study the reactions of individual retailers are investigated. For lettuce and chicken the vertical price relationships between retail and wholesale prices are estimated by an error correction approach, which is extended to test for structural breaks with a flexible time frame. The results indicate no impact of the Euro for most of the retail stores. However, about every fifth grocery store did react to the new currency by generally increasing its mark up significantly. This leads to the conclusion that money illusion might have a significant impact on the real adjustment of prices.Marketing,

Irreducibility of moduli of semistable Chains and applications to U(p,q)-Higgs bundles

We give necessary and sufficient conditions for moduli spaces of semistable chains on a curve to be irreducible and non-empty. This gives information on the irreducible components of the nilpotent cone of GL_n-Higgs bundles and the irreducible components of moduli of systems of Hodge bundles on curves. As we do not impose coprimality restrictions, we can apply this to prove connectedness for moduli spaces of U(p,q)-Higgs bundles.Comment: 13 pages; v2: minor corrections; to appear in the proceedings for the conference Hitchin 7