Earth Systems

Hydroclimatic analysis of climate change risks to global corporate assets in support of deep-dive valuation

Abstract: Climate change poses both risks and opportunities for business, now and in the future. However, investors, lenders, and insurers currently lack quantitative tools to view which companies will endure or flourish, and which companies are resilient or not. Measuring, managing, and reporting environmental impacts is not only important for the planet and the communities in which we work, but also essential for the future growth of our businesses. Among the key climate-related risks to society and business in particular are hydroclimatic risks (i.e., flood and drought). Projecting change in these risks are essential for the design, operation and management of public and private infrastructures. This is particularly true for large multi-national enterprises where their infrastructure and supply chains are located and connected across a wide-range of hydro-climatic zones. For the most part, public infrastructure in the industrial nations and private multinational production facilities have been designed to address current hydroclimatic risks. Regardless of these measures, we are faced with an unavoidable changing environment, which will alter hydro-climatic extremes and risks.

In light of these considerations, the primary objectives of this endeavor are to assess the change in hydro-climatic risks to the global landscape of a corporation’s infrastructure by providing: (1) weather and climate-induced impacts across the global hydrologic and water resources system; (2) conditions leading to weather, climate, and hydrologic extremes and their resultant hazards; and (3) risk-based projections of these changes for a selection of key facilities and supply-chain junctures. 

The analysis presented is performed on the actual global facilities of an anonymous global corporation, which hereafter will be referred to as GloCorp. A risk-based Indicator framework is developed. The framework utilizes an ensemble of hybrid frequency distribution (HFD) climate scenarios from the MIT Earth Systems Model with an enhanced version of the World Bank’s Climate Risk Hydro Indictors. The results suggest that by 2030, 61% of all facilities face a Medium or High Climate Risk. However, as climate change intensifies over the coming century, the impact on GloCorp’s facilities increases. By 2050, it is projected that 90% of all facilities face a Medium or High Climate Risk.

A decline in emissions of CFC-11 and related chemicals from eastern China

Abstract: Emissions of ozone-depleting substances, including trichlorofluoromethane (CFC11), have decreased since the mid-1980s in response to the Montreal Protocol. In recent years, an unexpected increase in CFC-11 emissions beginning in 2013 has been reported, with much of the global rise attributed to emissions from eastern China.

Here we use high-frequency atmospheric mole fraction observations from Gosan, South Korea and Hateruma, Japan, together with atmospheric chemical transport-model simulations, to investigate regional CFC-11 emissions from eastern China. We find that CFC-11 emissions returned to pre-2013 levels in 2019 (5.0 ± 1.0 gigagrams per year in 2019, compared to 7.2 ± 1.5 gigagrams per year for 2008–2012, ±1 standard deviation), decreasing by 10 ± 3 gigagrams per year since 2014–2017. Furthermore, we find that in this region, carbon tetrachloride (CCl4) and dichlorodifluoromethane (CFC-12) emissions—potentially associated with CFC-11 production—were higher than expected after 2013 and then declined one to two years before the CFC-11 emissions reduction.

This suggests that CFC-11 production occurred in eastern China after the mandated global phase-out, and that there was a subsequent decline in production during 2017–2018. We estimate that the amount of the CFC-11 bank (the amount of CFC-11 produced, but not yet emitted) in eastern China is up to 112 gigagrams larger in 2019 compared to pre-2013 levels, probably as a result of recent production. Nevertheless, it seems that any substantial delay in ozone-layer recovery has been avoided, perhaps owing to timely reporting and subsequent action by industry and government in China.

As the United States transitions from one administration bent on rolling back climate regulations to another that aims to accelerate climate action, it seems as good a time as any to take stock. What do scientists understand about today’s climate; how much worse are hurricanes, wildfires, heat waves and other climate impacts going to get in coming decades, and what does the country and world need to do to reduce the likelihood and severity of those impacts?

Climate change: Where we are, where we’re headed, what we can do
A consistent framework for uncertainty in coupled human-Earth system models

Abstract: Addressing climate change is ultimately a challenge of risk management, which requires an understanding of the likelihood of potential outcomes. We provide integrated, probabilistic socio-economic and climate projections obtained using updated estimates of probability distributions for key parameters in both the human and Earth system components of the MIT Integrated Global System Model (IGSM).

The Reference scenario results in median end-of-century warming of 3.5oC and a 90% range of 2.8-4.3oC, which is lower than the median of 5.7oC from a prior study using a previous version of the IGSM. About 0.5oC of the difference is due to updated estimates in the human system and the rest of the difference is explained by changes in Earth system estimates.

Our results show that climate policy lowers the upper tail of temperature change distributions more than the median, and that even relatively modest policies can significantly reduce the likelihood of high global temperature outcomes. Human system uncertainties contribute more to uncertainty in projected CO2 concentrations and total radiative forcing, while Earth system uncertainties have the greatest influence on temperature and precipitation. Including additional uncertain inputs does not automatically increase the outcome range because uncertainties can offset one another.

Results also show how policy costs can vary greatly among regions.  As we improve understanding of underlying technology and economic factors as well as Earth system response to human forcing, further updating of these estimates of uncertainty can make an important contribution to decision-making about mitigation and adaptation.

Methyl Chloroform continues to constrain the hydroxyl (OH) variability in the troposphere

Abstract: Trends and variability in tropospheric hydroxyl (OH) radicals influence budgets of many greenhouse gases, air pollutant species and ozone depleting substances. Estimations of tropospheric OH trends and variability based on budget analysis of methyl chloroform (CH3CCl3), and process‐based chemistry transport models often produce conflicting results. Here we use a previously tested transport model to simulate atmospheric CH3CCl3 for the period 1985‐2018. Based on mismatches between model output and observations, we derive consistent anomalies in the inverse lifetime of CH3CCl3 (KG) using measurements from two independent observational networks (NOAA and AGAGE). Our method allows a separation between “physical” (transport, temperature) and “chemical” (i.e., abundance) influences on OH+CH3CCl3 reaction rate in the atmosphere. Small increases in KG due to “physical” influences are mostly driven by increases in the temperature‐dependent reaction between OH and CH3CCl3 and resulted in a smoothly varying increase of 0.80 % decade‐1 . Chemical effects on KG, linked to global changes in OH sources and sinks, show larger year‐to‐year variations (∼2‐3%), and have a negative correlation with the El Niño Southern Oscillation. A significant positive trend in KG can be derived after 2001, but it persists only through 2015 and only if we assume that CH3CCl3 emissions decayed more slowly over time than our best estimate suggests. If global CH3CCl3 emissions dropped below 3 Gg yr‐1 after 2015, recent CH3CCl3 measurements indicate that the 2015‐2018 loss rate of CH3CCl3 due to reaction with OH is comparable to its value two decades ago.

The increasing atmospheric burden of the greenhouse gas sulfur hexafluoride (SF6)

Abstract: We report a 40-year history of SF6 atmospheric mole fractions measured at the Advanced Global Atmospheric Gases Experiment (AGAGE) monitoring sites, combined with archived air samples, to determine emission estimates from 1978 to 2018. Previously we reported a global emission rate of 7.3±0.6 Gg yr−1 in 2008 and over the past decade emissions have continued to increase by about 24 % to 9.04±0.35 Gg yr−1 in 2018. We show that changing patterns in SF6 consumption from developed (Kyoto Protocol Annex-1) to developing countries (non-Annex-1) and the rapid global expansion of the electric power industry, mainly in Asia, have increased the demand for SF6-insulated switchgear, circuit breakers, and transformers. The large bank of SF6 sequestered in this electrical equipment provides a substantial source of emissions from maintenance, replacement, and continuous leakage. Other emissive sources of SF6 occur from the magnesium, aluminium, and electronics industries as well as more minor industrial applications. More recently, reported emissions, including those from electrical equipment and metal industries, primarily in the Annex-1 countries, have declined steadily through substitution of alternative blanketing gases and technological improvements in less emissive equipment and more efficient industrial practices. Nevertheless, there are still demands for SF6 in Annex-1 countries due to economic growth, as well as continuing emissions from older equipment and additional emissions from newly installed SF6-insulated electrical equipment, although at low emission rates. In addition, in the non-Annex-1 countries, SF6 emissions have increased due to an expansion in the growth of the electrical power, metal, and electronics industries to support their continuing development.

There is an annual difference of 2.5–5 Gg yr−1 (1990–2018) between our modelled top-down emissions and the UNFCCC-reported bottom-up emissions (United Nations Framework Convention on Climate Change), which we attempt to reconcile through analysis of the potential contribution of emissions from the various industrial applications which use SF6. We also investigate regional emissions in East Asia (China, S. Korea) and western Europe and their respective contributions to the global atmospheric SF6 inventory. On an average annual basis, our estimated emissions from the whole of China are approximately 10 times greater than emissions from western Europe. In 2018, our modelled Chinese and western European emissions accounted for ∼36 % and 3.1 %, respectively, of our global SF6 emissions estimate.

Pages

Subscribe to Earth Systems