Related Experiment Video
Updated: Jan 21, 2026
09:34
Extraction and Characterization of Surfactants from Atmospheric Aerosols
Published on: April 21, 2017
17.3K
Weak average liquid-cloud-water response to anthropogenic aerosols
Velle Toll1,2, Matthew Christensen3, Johannes Quaas4
1Department of Meteorology, University of Reading, Reading, UK. velle.toll@ut.ee.
Nature
|August 2, 2019
Summary
Anthropogenic aerosols cause a weak decrease in cloud water, contrary to previous theories. This finding reduces uncertainty in climate change projections by showing aerosols have a smaller cooling effect than expected.
Area of Science:
- Atmospheric Science
- Climate Science
- Cloud Physics
Background:
- Anthropogenic aerosols influence Earth's climate by interacting with clouds.
- Aerosol-induced cloud water increases, via suppressed rain, were hypothesized to cause significant cooling.
- This implied high sensitivity of surface temperature to anthropogenic forcing.
Purpose of the Study:
- To provide direct observational evidence of aerosol effects on cloud water.
- To quantify the impact of aerosols on liquid-phase cloud water content.
- To reassess the climate cooling effect attributed to aerosols.
Main Methods:
- Direct observation of polluted clouds downwind of various anthropogenic sources.
- Comparison of cloud water content in polluted versus unpolluted clouds.
- Estimation of aerosol-induced changes in cloud water and their contribution to climate forcing.
Main Results:
- Aerosols cause a relatively weak average decrease in liquid-phase cloud water.
- Aerosol effects of suppressed rain (increasing water) and enhanced evaporation (decreasing water) partially cancel.
- Observed cloud water decrease offsets 23% of the cooling effect from increased cloud droplet concentration.
Conclusions:
- The hypothesis of substantial climate cooling due to increased cloud water is invalidated.
- Aerosol-cloud interactions have a weaker cooling effect than previously estimated.
- Uncertainty in future climate projections is reduced.
Related Concept Videos
03:21Weak Base Solutions
24.9K
Some compounds produce hydroxide ions when dissolved by chemically reacting with water molecules. In all cases, these compounds react only partially and so are classified as weak bases. These types of compounds are also abundant in nature and important commodities in various technologies. For example, global production of the weak base ammonia is typically well over 100 metric tons annually, being widely used as an agricultural fertilizer, a raw material for chemical synthesis of other...
24.9K
04:02Weak Acid Solutions
42.3K
Few compounds act as strong acids. A far greater number of compounds behave as weak acids and only partially react with water, leaving a large majority of dissolved molecules in their original form and generating a relatively small amount of hydronium ions. Weak acids are commonly encountered in nature, being the substances partly responsible for the tangy taste of citrus fruits, the stinging sensation of insect bites, and the unpleasant smells associated with body odor. A familiar example of a...
42.3K
01:08Titration of a Weak Acid with a Weak Base
4.8K
Weak acids and bases do not undergo dissociation completely, and titrations between these two are rarely studied. When such studies are performed, say, for the titration of a weak acid with a weak base, the titration curve plots the change in pH as a function of the volume of base added. Take the titration of acetic acid with ammonia, for instance. During the titration, these two species form ammonium acetate and water, but the pH change is slow and gradual.
As a result, there is no simple...
As a result, there is no simple...
4.8K
03:55Titration Calculations: Weak Acid - Strong Base
49.1K
Calculating pH for Titration Solutions: Weak Acid/Strong Base
For the titration of 25.00 mL of 0.100 M CH3CO2H with 0.100 M NaOH, the reaction can be represented as:
For the titration of 25.00 mL of 0.100 M CH3CO2H with 0.100 M NaOH, the reaction can be represented as:
49.1K
01:00The Water Cycle
28.1K
The Earth’s hydrosphere includes all of the areas where the storage and movement of water occurs. Since water is the basis of all living processes, the cycling of water is extremely important to ecosystem dynamics.
28.1K
01:30Average Acceleration
12.9K
The importance of understanding acceleration spans our day-to-day experiences, as well as the vast reaches of outer space and the tiny world of subatomic physics. In everyday conversation, to accelerate means to speed up. For instance, we are familiar with the acceleration of our car; the harder we apply our foot to the gas pedal, the faster we accelerate. The greater the acceleration, the greater the change in velocity over a given time. Acceleration is widely seen in experimental physics. In...
12.9K