Drivers of Precipitation Change: An Energetic Understanding

The response of the hydrological cycle to climate forcings can be understood within the atmospheric energy budget framework. In this study precipitation and energy budget responses to five forcing agents are analyzed using 10 climate models from the Precipitation Driver Response Model Intercomparison Project (PDRMIP). Precipitation changes are split into a forcing-dependent fast response and a temperature-driven hydrological sensitivity. Globally, when normalized by top-of-atmosphere (TOA) forcing, fast precipitation changes are most sensitive to strongly absorbing drivers (CO2, black carbon). However, over land fast precipitation changes are most sensitive to weakly absorbing drivers (sulfate, solar) and are linked to rapid circulation changes. Despite this, land-mean fast responses to CO2 and black carbon exhibit more intermodel spread. Globally, the hydrological sensitivity is consistent across forcings, mainly associated with increased longwave cooling, which is highly correlated with intermodel spread. The land-mean hydrological sensitivity is weaker, consistent with limited moisture availability. The PDRMIP results are used to construct a simple model for land-mean and sea-mean precipitation change based on sea surface temperature change and TOA forcing. The model matches well with CMIP5 ensemble mean historical and future projections, and is used to understand the contributions of different drivers. During the twentieth century, temperature-driven intensification of land-mean precipitation has been masked by fast precipitation responses to anthropogenic sulfate and volcanic forcing, consistent with the small observed trend. However, as projected sulfate forcing decreases, and warming continues, land-mean precipitation is expected to increase more rapidly, and may become clearly observable by the mid-twenty-first century.

Download Full-text

Amplified Arctic precipitation increases are driven by atmospheric radiative cooling

10.5194/egusphere-egu21-2439 ◽

2021 ◽

Author(s):

Felix Pithan ◽

Thomas Jung

Keyword(s):

Water Vapour ◽

Energy Budget ◽

Precipitation Change ◽

Radiative Cooling ◽

High Latitudes ◽

Local Warming ◽

The Tropics ◽

Precipitation Changes ◽

Relative Change ◽

Circulation Changes

<p>As the climate warms, the amount of water vapour in the atmosphere increases by about 7 % per K, following the clausius-clapeyron relation. Globally averaged precipitation only increases by about 1-2 % per K of warming, as it is constrained by the atmospheric energy budget rather than the availability of moisture in the atmosphere. In the Tropics, zonally averaged precipitation mostly increases in the ITCZ near the equator and decreases in the subtropical dry zones (rich get richer, poor get poorer). A fundamental explanation of extratropical precipitation change has yet to be provided.</p><p>Here, we show that the structure of zonal mean mid-latitude precipitation changes is largely controlled by circulation changes, whereas amplified Arctic precipitation change is linked to increased atmospheric radiative cooling. The relative change in precipitation per unit of local warming is greater at high latitudes than anywhere else.</p>

Download Full-text

Increased water vapour lifetime due to global warming

10.5194/acp-2019-121 ◽

2019 ◽

Cited By ~ 1

Author(s):

Øivind Hodnebrog ◽

Gunnar Myhre ◽

Bjørn H. Samset ◽

Kari Alterskjær ◽

Timothy Andrews ◽

...

Keyword(s):

Global Warming ◽

Water Vapour ◽

Solar Irradiance ◽

Climate Models ◽

Hydrological Cycle ◽

Global Climate ◽

Global Climate Models ◽

Climate Projections ◽

Surface Temperature Change ◽

Surface Warming

Abstract. The relationship between changes in integrated water vapour (IWV) and precipitation can be characterized by quantifying changes in atmospheric water vapour lifetime. Precipitation isotope ratios correlate with this lifetime, a relationship that helps understand dynamical processes and may lead to improved climate projections. We investigate how water vapour and its lifetime respond to different drivers of climate change, such as greenhouse gases and aerosols. Results from 11 global climate models have been used, based on simulations where CO2, methane, solar irradiance, black carbon (BC), and sulphate have been perturbed separately. A lifetime increase from 8 to 10 days is projected between 1986–2005 and 2081–2100, under a business-as-usual pathway. By disentangling contributions from individual climate drivers, we present a physical understanding of how global warming slows down the hydrological cycle, due to longer lifetime, but still amplifies the cycle due to stronger precipitation/evaporation fluxes. The feedback response of IWV to surface temperature change differs somewhat between drivers. Fast responses amplify these differences and lead to net changes in IWV per degree surface warming ranging from 6.4±0.9 %/K for sulphate to 9.8±2 %/K for BC. While BC is the driver with the strongest increase in IWV per degree surface warming, it is also the only driver with a reduction in precipitation per degree surface warming. Consequently, increases in BC aerosol concentrations yield the strongest slowdown of the hydrological cycle among the climate drivers studied, with a change in water vapour lifetime per degree surface warming of 1.1±0.4 days/K, compared to less than 0.5 days/K for the other climate drivers (CO2, methane, solar irradiance, sulphate).

Download Full-text

Water vapour adjustments and responses differ between climate drivers

Atmospheric Chemistry and Physics ◽

10.5194/acp-19-12887-2019 ◽

2019 ◽

Vol 19 (20) ◽

pp. 12887-12899 ◽

Cited By ~ 3

Author(s):

Øivind Hodnebrog ◽

Gunnar Myhre ◽

Bjørn H. Samset ◽

Kari Alterskjær ◽

Timothy Andrews ◽

...

Keyword(s):

Climate Change ◽

Water Vapour ◽

Climate Models ◽

Hydrological Cycle ◽

Global Climate ◽

Global Climate Models ◽

Climate Feedback ◽

Global Changes ◽

Important Indicator ◽

Surface Temperature Change

Abstract. Water vapour in the atmosphere is the source of a major climate feedback mechanism and potential increases in the availability of water vapour could have important consequences for mean and extreme precipitation. Future precipitation changes further depend on how the hydrological cycle responds to different drivers of climate change, such as greenhouse gases and aerosols. Currently, neither the total anthropogenic influence on the hydrological cycle nor that from individual drivers is constrained sufficiently to make solid projections. We investigate how integrated water vapour (IWV) responds to different drivers of climate change. Results from 11 global climate models have been used, based on simulations where CO2, methane, solar irradiance, black carbon (BC), and sulfate have been perturbed separately. While the global-mean IWV is usually assumed to increase by ∼7 % per kelvin of surface temperature change, we find that the feedback response of IWV differs somewhat between drivers. Fast responses, which include the initial radiative effect and rapid adjustments to an external forcing, amplify these differences. The resulting net changes in IWV range from 6.4±0.9 % K−1 for sulfate to 9.8±2 % K−1 for BC. We further calculate the relationship between global changes in IWV and precipitation, which can be characterized by quantifying changes in atmospheric water vapour lifetime. Global climate models simulate a substantial increase in the lifetime, from 8.2±0.5 to 9.9±0.7 d between 1986–2005 and 2081–2100 under a high-emission scenario, and we discuss to what extent the water vapour lifetime provides additional information compared to analysis of IWV and precipitation separately. We conclude that water vapour lifetime changes are an important indicator of changes in precipitation patterns and that BC is particularly efficient in prolonging the mean time, and therefore likely the distance, between evaporation and precipitation.

Download Full-text

Contribution of historical precipitation change to US flood damages

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2017524118 ◽

2021 ◽

Vol 118 (4) ◽

pp. e2017524118

Author(s):

Frances V. Davenport ◽

Marshall Burke ◽

Noah S. Diffenbaugh

Keyword(s):

United States ◽

Global Warming ◽

Climate Models ◽

State Level ◽

The United States ◽

Precipitation Change ◽

Cumulative Impact ◽

Flood Damages ◽

Precipitation Changes ◽

The Impact

Precipitation extremes have increased across many regions of the United States, with further increases anticipated in response to additional global warming. Quantifying the impact of these precipitation changes on flood damages is necessary to estimate the costs of climate change. However, there is little empirical evidence linking changes in precipitation to the historically observed increase in flood losses. We use >6,600 reports of state-level flood damage to quantify the historical relationship between precipitation and flood damages in the United States. Our results show a significant, positive effect of both monthly and 5-d state-level precipitation on state-level flood damages. In addition, we find that historical precipitation changes have contributed approximately one-third of cumulative flood damages over 1988 to 2017 (primary estimate 36%; 95% CI 20 to 46%), with the cumulative impact of precipitation change totaling $73 billion (95% CI 39 to $91 billion). Further, climate models show that anthropogenic climate forcing has increased the probability of exceeding precipitation thresholds at the extremely wet quantiles that are responsible for most flood damages. Climate models project continued intensification of wet conditions over the next three decades, although a trajectory consistent with UN Paris Agreement goals significantly curbs that intensification. Taken together, our results quantify the contribution of precipitation trends to recent increases in flood damages, advance estimates of the costs associated with historical greenhouse gas emissions, and provide further evidence that lower levels of future warming are very likely to reduce financial losses relative to the current global warming trajectory.

Download Full-text

Metrics for linking emissions of gases and aerosols to global precipitation changes

Earth System Dynamics ◽

10.5194/esd-6-525-2015 ◽

2015 ◽

Vol 6 (2) ◽

pp. 525-540 ◽

Cited By ~ 16

Author(s):

K. P. Shine ◽

R. P. Allan ◽

W. J. Collins ◽

J. S. Fuglestvedt

Keyword(s):

Surface Temperature ◽

Temperature Change ◽

Radiative Forcing ◽

Precipitation Change ◽

Pulse Emission ◽

Surface Temperature Change ◽

Input Parameters ◽

Global Temperature Change ◽

Precipitation Changes ◽

Global Precipitation

Abstract. Recent advances in understanding have made it possible to relate global precipitation changes directly to emissions of particular gases and aerosols that influence climate. Using these advances, new indices are developed here called the Global Precipitation-change Potential for pulse (GPPP) and sustained (GPPS) emissions, which measure the precipitation change per unit mass of emissions. The GPP can be used as a metric to compare the effects of different emissions. This is akin to the global warming potential (GWP) and the global temperature-change potential (GTP) which are used to place emissions on a common scale. Hence the GPP provides an additional perspective of the relative or absolute effects of emissions. It is however recognised that precipitation changes are predicted to be highly variable in size and sign between different regions and this limits the usefulness of a purely global metric. The GPPP and GPPS formulation consists of two terms, one dependent on the surface temperature change and the other dependent on the atmospheric component of the radiative forcing. For some forcing agents, and notably for CO2, these two terms oppose each other – as the forcing and temperature perturbations have different timescales, even the sign of the absolute GPPP and GPPS varies with time, and the opposing terms can make values sensitive to uncertainties in input parameters. This makes the choice of CO2 as a reference gas problematic, especially for the GPPS at time horizons less than about 60 years. In addition, few studies have presented results for the surface/atmosphere partitioning of different forcings, leading to more uncertainty in quantifying the GPP than the GWP or GTP. Values of the GPPP and GPPS for five long- and short-lived forcing agents (CO2, CH4, N2O, sulphate and black carbon – BC) are presented, using illustrative values of required parameters. The resulting precipitation changes are given as the change at a specific time horizon (and hence they are end-point metrics) but it is noted that the GPPS can also be interpreted as the time-integrated effect of a pulse emission. Using CO2 as a references gas, the GPPP and GPPS for the non-CO2 species are larger than the corresponding GTP values. For BC emissions, the atmospheric forcing is sufficiently strong that the GPPS is opposite in sign to the GPPS. The sensitivity of these values to a number of input parameters is explored. The GPP can also be used to evaluate the contribution of different emissions to precipitation change during or after a period of emissions. As an illustration, the precipitation changes resulting from emissions in 2008 (using the GPPP) and emissions sustained at 2008 levels (using the GPPS) are presented. These indicate that for periods of 20 years (after the 2008 emissions) and 50 years (for sustained emissions at 2008 levels) methane is the dominant driver of positive precipitation changes due to those emissions. For sustained emissions, the sum of the effect of the five species included here does not become positive until after 50 years, by which time the global surface temperature increase exceeds 1 K.

Download Full-text

Observational constraints reduce estimates of the global mean climate relevance of black carbon

10.21203/rs.3.rs-691895/v1 ◽

2021 ◽

Author(s):

Gunnar Myhre ◽

Bjørn Samset ◽

Camilla Weum Stjern ◽

Øivind Hodnebrog ◽

Ryan Kramer ◽

...

Keyword(s):

Black Carbon ◽

Radiative Forcing ◽

Climate Models ◽

Absorption Efficiency ◽

Surface Temperature Change ◽

A Value ◽

Rapid Adjustment ◽

Effective Radiative Forcing ◽

Mean Climate ◽

Global Mean

Abstract How emissions of black carbon (BC) aerosols affect the climate is still uncertain, due to incomplete knowledge of its sources, optical properties and atmospheric processes such as transport, removal and impact on clouds. Here we constrain simulations from four climate models with observations of atmospheric BC concentrations and absorption efficiency, and the most recent emission inventories, to show that the current global mean surface temperature change from anthropogenic BC emissions is likely to be weak at +0.03 ±0.02K. Atmospheric rapid adjustment processes are found to reduce the top of atmosphere radiative imbalance relative to instantaneous radiative forcing (direct aerosol effect) by almost 50% as a multi-model mean. Furthermore, constraining the models to reproduce observational estimates of the atmospheric vertical profile reduces BC effective radiative forcing to 0.08 W m-2, a value more than 50% lower than in unconstrained simulations. Our results imply a need to revisit commonly used climate metrics such as the global warming potential of BC. This value (for a 100-year time horizon) reduces from 680 when neglecting rapid adjustments and using an unconstrained BC profile to our best estimate of 160 ±120.

Download Full-text

Understanding the Intermodel Spread in Global-Mean Hydrological Sensitivity*

Journal of Climate ◽

10.1175/jcli-d-15-0351.1 ◽

2016 ◽

Vol 29 (2) ◽

pp. 801-817 ◽

Cited By ~ 44

Author(s):

Dagmar Fläschner ◽

Thorsten Mauritsen ◽

Bjorn Stevens

Keyword(s):

Surface Temperature ◽

Temperature Response ◽

Tropospheric Temperature ◽

Surface Temperature Change ◽

Surface Warming ◽

Kernel Analysis ◽

Relative Contribution ◽

Hydrological Sensitivity ◽

Precipitation Changes ◽

Global Mean

Abstract This paper assesses intermodel spread in the slope of global-mean precipitation change ΔP with respect to surface temperature change. The ambiguous estimates in the literature for this slope are reconciled by analyzing four experiments from phase 5 of CMIP (CMIP5) and considering different definitions of the slope. The smallest intermodel spread (a factor of 1.5 between the highest and lowest estimate) is found when using a definition that disentangles temperature-independent precipitation changes (the adjustments) from the slope of the temperature-dependent precipitation response; here this slope is referred to as the hydrological sensitivity parameter η. The estimates herein show that η is more robust than stated in most previous work. The authors demonstrate that adjustments and η estimated from a steplike quadrupling CO2 experiment serve well to predict ΔP in a transient CO2 experiment. The magnitude of η is smaller in the coupled ocean–atmosphere quadrupling CO2 experiment than in the noncoupled atmosphere-only experiment. The offset in magnitude due to coupling suggests that intermodel spread may undersample uncertainty. Also assessed are the relative contribution of η, the surface warming, and the adjustment on the spread in ΔP on different time scales. Intermodel variation of both η and the adjustment govern the spread in ΔP in the years immediately after the abrupt forcing change. In equilibrium, the uncertainty in ΔP is dominated by uncertainty in the equilibrium surface temperature response. A kernel analysis reveals that intermodel spread in η is dominated by intermodel spread in tropical lower tropospheric temperature and humidity changes and cloud changes.

Download Full-text

Are Changes in Global Precipitation Constrained by the Tropospheric Energy Budget?

Journal of Climate ◽

10.1175/2008jcli2135.1 ◽

2009 ◽

Vol 22 (3) ◽

pp. 499-517 ◽

Cited By ~ 39

Author(s):

F. Hugo Lambert ◽

Myles R. Allen

Keyword(s):

Greenhouse Gas ◽

Black Carbon ◽

Energy Budget ◽

General Circulation ◽

Circulation Model ◽

First Century ◽

Aerosol Forcing ◽

Twenty First Century ◽

Precipitation Changes ◽

Global Precipitation

Abstract A tropospheric energy budget argument is used to analyze twentieth-century precipitation changes. It is found that global and ocean-mean general circulation model (GCM) precipitation changes can be understood as being due to the competing direct and surface-temperature-dependent effects of external climate forcings. In agreement with previous work, precipitation is found to respond more strongly to anthropogenic and volcanic sulfate aerosol and solar forcing than to greenhouse gas and black carbon aerosol forcing per unit temperature. This is due to the significant direct effects of greenhouse gas and black carbon forcing. Given that the relative importance of different forcings may change in the twenty-first century, the ratio of global precipitation change to global temperature change may be quite different. Differences in GCM twentieth- and twenty-first-century values are tractable via the energy budget framework in some, but not all, models. Changes in land-mean precipitation, on the other hand, cannot be understood at all with the method used here, even if land–ocean heat transfer is considered. In conclusion, the tropospheric energy budget is a useful concept for understanding the precipitation response to different forcings but it does not fully explain precipitation changes even in the global mean.

Download Full-text

Regions of intensification of extreme snowfall under future warming

Scientific Reports ◽

10.1038/s41598-021-95979-4 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Lennart Quante ◽

Sven N. Willner ◽

Robin Middelanis ◽

Anders Levermann

Keyword(s):

Climate Change ◽

Global Warming ◽

Observational Data ◽

Climate Models ◽

Hydrological Cycle ◽

Global Climate ◽

Global Climate Models ◽

Average Intensity ◽

High Latitudes ◽

Future Warming

AbstractDue to climate change the frequency and character of precipitation are changing as the hydrological cycle intensifies. With regards to snowfall, global warming has two opposing influences; increasing humidity enables intense snowfall, whereas higher temperatures decrease the likelihood of snowfall. Here we show an intensification of extreme snowfall across large areas of the Northern Hemisphere under future warming. This is robust across an ensemble of global climate models when they are bias-corrected with observational data. While mean daily snowfall decreases, both the 99th and the 99.9th percentiles of daily snowfall increase in many regions in the next decades, especially for Northern America and Asia. Additionally, the average intensity of snowfall events exceeding these percentiles as experienced historically increases in many regions. This is likely to pose a challenge to municipalities in mid to high latitudes. Overall, extreme snowfall events are likely to become an increasingly important impact of climate change in the next decades, even if they will become rarer, but not necessarily less intense, in the second half of the century.

Download Full-text

Snowfall-albedo feedbacks could have led to deglaciation of snowball Earth starting from mid-latitudes

Communications Earth & Environment ◽

10.1038/s43247-021-00160-4 ◽

2021 ◽

Vol 2 (1) ◽

Author(s):

Philipp de Vrese ◽

Tobias Stacke ◽

Jeremy Caves Rugenstein ◽

Jason Goodman ◽

Victor Brovkin

Keyword(s):

Carbon Dioxide ◽

Atmospheric Carbon Dioxide ◽

Climate Models ◽

Hydrological Cycle ◽

High Surface ◽

Dust Deposition ◽

Carbon Dioxide Concentrations ◽

Maximum Temperatures ◽

Carbon Dioxide Levels ◽

Earth’S Climate

AbstractSimple and complex climate models suggest a hard snowball – a completely ice-covered planet – is one of the steady-states of Earth’s climate. However, a seemingly insurmountable challenge to the hard-snowball hypothesis lies in the difficulty in explaining how the planet could have exited the glaciated state within a realistic range of atmospheric carbon dioxide concentrations. Here, we use simulations with the Earth system model MPI-ESM to demonstrate that terminal deglaciation could have been triggered by high dust deposition fluxes. In these simulations, deglaciation is not initiated in the tropics, where a strong hydrological cycle constantly regenerates fresh snow at the surface, which limits the dust accumulation and snow aging, resulting in a high surface albedo. Instead, comparatively low precipitation rates in the mid-latitudes in combination with high maximum temperatures facilitate lower albedos and snow dynamics that – for extreme dust fluxes – trigger deglaciation even at present-day carbon dioxide levels.

Download Full-text