<p>This phenomenon is known as <a href="https://en.wikipedia.org/wiki/Global_dimming" rel="noreferrer">global dimming</a>.</p>

<p>It was due to the particles and aerosols mostly released by combustion of fossil fuels such as diesel. Those particles block the radiation from the sun, so they have a cooling effect. For some decades this effect counterbalanced the warming effect of greenhouse gases, although it is no longer the case at a global scale (see for instance <a href="https://doi.org/10.1029/2006GL028031" rel="noreferrer">Wild et al. 2007</a>). Particles emission has been reduced thanks to better engines and new regulations, which stopped their masking effect on global warming. Which is a good thing since those particles have a serious impact on health.</p>

CC BY-SA 4.0
2019-12-23T11:51:40.887Z
Highly related: https://skepticalscience.com/global-cooling-mid-20th-century-basic.htm .
David Hammen
CC BY-SA 4.0
2019-12-23T12:46:22.520Z
"which is a good thing since those particles have a serious impact on health". Do you know any study with empirical evidence which sustains that? They did something similar with an experiment last year in the upper atmosphere to see if they could reduce temperature and IIRC they said it worked
Pablo
CC BY-SA 4.0
2019-12-23T14:42:29.053Z
The effect of particles on health (lungs mostly) is well known, that's why we took those regulations in the first place. But I guess you mean if we did some kind of geoengineering by spreading particles in the atmosphere? I don't know. I think it might work to cool the planet for a while, but the particles would eventually sediment back to the ground, where they would be harmful to people. And you'd have to spread more and more of them to keep the effect going...
Jean-Marie Prival
CC BY-SA 4.0
2019-12-23T15:14:30.280Z
@ebv Yes, it's fighting the consequences of global warming instead of tackling the source of the problem...
Jean-Marie Prival
CC BY-SA 4.0
2019-12-23T17:48:21.130Z
I had always understood it to be in large part a result of the sulfur dioxide emissions from coal-fired power plants.  Once emissions-control regulations reduced those (and so reduced acid rain &c) the cooling effect disappeared, since SO2 doesn't have a very long atmospheric residence time.  You can see similar short-term cooling effects from large volcanic eruptions, e.g. https://earthobservatory.nasa.gov/images/1510/global-effects-of-mount-pinatubo
jamesqf
CC BY-SA 4.0
2019-12-24T13:29:22.317Z
@Jean-MariePrival https://www.ncbi.nlm.nih.gov/pubmed/475153 Controlled exposures of human volunteers to sulfate aerosols. Health effects and aerosol characterization.We found little or no evidence of adverse health effects from 2-hour multiple-day exposures to any of the compounds at "worst case" ambient concentrations. That's why I asked if you knew studies with empirical evidence, since a lot of mainstream assertions might be true or not. By the way, I find strange that in 3 decades of having those in the air in toxic levels, we didnt hear catastrophic annoucements from the media about it.
Pablo
CC BY-SA 4.0
2019-12-24T13:31:23.990Z
And.. https://www.nature.com/articles/d41586-018-07533-4
Pablo
CC BY-SA 4.0
2019-12-25T05:31:03.090Z
@Pablo: There was quite a lot in the media in the 1970s and 1980 about the effects of sulfate emissions.  It's just that it wasn't primarily a matter of direct human health, but of the effects on lakes & forests: https://en.wikipedia.org/wiki/Acid_rain#History
jamesqf
CC BY-SA 4.0
2019-12-23T09:52:40.670Z
2019-12-23T09:52:40.670Z
Jean-Marie Prival
<p>If I understand the information from this link correctly,</p>
<p><a href="https://en.wikipedia.org/wiki/Instrumental_temperature_record" rel="nofollow noreferrer">Instrumental temperature record</a></p>
<p>between 1950 to 1980 there were negative temperature anomalies in the years of those decades.</p>
<div class="s-table-container">
<table class="s-table">
<thead>
<tr>
<th>decade</th>
<th style="text-align: right;">difference (°C)</th>
<th style="text-align: right;">difference (°F)</th>
</tr>
</thead>
<tbody>
<tr>
<td>1950–1959</td>
<td style="text-align: right;">−0.02</td>
<td style="text-align: right;">-0.0360</td>
</tr>
<tr>
<td>1960–1969</td>
<td style="text-align: right;">−0.014</td>
<td style="text-align: right;">−0.0252</td>
</tr>
<tr>
<td>1970–1979</td>
<td style="text-align: right;">−0.001</td>
<td style="text-align: right;">−0.0018</td>
</tr>
</tbody>
</table>
</div>
<p>This seems odd considering massive oil consumption started in 1880 IIRC, and by 1980 over 350 billions of oil barrels were already consumed (much more probably, since the data before 1950 isn't considered because there weren't reliable records).</p>
<p>Why was there a negative temperature anomaly between 1950 to 1980?</p>

CC BY-SA 4.0
2019-12-23T12:53:24.223Z
I can only see a temperature top under ww2. Also, accumulation of energy in sea affect global warming and so do long time changes in ocean currents.
Lehs
<climate-change><temperature>
Why was there a negative temperature anomaly between 1950 to 1980?
Pablo
# Why was there a negative temperature anomaly between 1950 to 1980?

(Asked by: username_0 on 2019-12-23)

If I understand the information from this link correctly,

[Instrumental temperature record](https://en.wikipedia.org/wiki/Instrumental_temperature_record)

between 1950 to 1980 there were negative temperature anomalies in the years of those decades.

| decade | difference (°C) | difference (°F) |
| --- | --- | --- |
| 1950–1959 | −0.02 | -0.0360 |
| 1960–1969 | −0.014 | −0.0252 |
| 1970–1979 | −0.001 | −0.0018 |

This seems odd considering massive oil consumption started in 1880 IIRC, and by 1980 over 350 billions of oil barrels were already consumed (much more probably, since the data before 1950 isn't considered because there weren't reliable records).

Why was there a negative temperature anomaly between 1950 to 1980?

**Tags:** climate-change, temperature

> **Comments:**
> **username_1**: I can only see a temperature top under ww2. Also, accumulation of energy in sea affect global warming and so do long time changes in ocean currents.  

---

## 1 answers

### Answer by username_2 on 2019-12-23. Score: 24 | Accepted answer

This phenomenon is known as [global dimming](https://en.wikipedia.org/wiki/Global_dimming).

It was due to the particles and aerosols mostly released by combustion of fossil fuels such as diesel. Those particles block the radiation from the sun, so they have a cooling effect. For some decades this effect counterbalanced the warming effect of greenhouse gases, although it is no longer the case at a global scale (see for instance [Wild et al. 2007](https://doi.org/10.1029/2006GL028031)). Particles emission has been reduced thanks to better engines and new regulations, which stopped their masking effect on global warming. Which is a good thing since those particles have a serious impact on health.

> **Comments:**
> **username_3**: Highly related: https://skepticalscience.com/global-cooling-mid-20th-century-basic.htm .  
> **username_0**: "which is a good thing since those particles have a serious impact on health". Do you know any study with empirical evidence which sustains that? They did something similar with an experiment last year in the upper atmosphere to see if they could reduce temperature and IIRC they said it worked  
> **username_2**: The effect of particles on health (lungs mostly) is well known, that's why we took those regulations in the first place. But I guess you mean if we did some kind of geoengineering by spreading particles in the atmosphere? I don't know. I think it might work to cool the planet for a while, but the particles would eventually sediment back to the ground, where they would be harmful to people. And you'd have to spread more and more of them to keep the effect going...  
> **username_2**: @ebv Yes, it's fighting the consequences of global warming instead of tackling the source of the problem...  
> **username_4**: I had always understood it to be in large part a result of the sulfur dioxide emissions from coal-fired power plants.  Once emissions-control regulations reduced those (and so reduced acid rain &c) the cooling effect disappeared, since SO2 doesn't have a very long atmospheric residence time.  You can see similar short-term cooling effects from large volcanic eruptions, e.g. https://earthobservatory.nasa.gov/images/1510/global-effects-of-mount-pinatubo  
> **username_0**: @username_2 https://www.ncbi.nlm.nih.gov/pubmed/475153 Controlled exposures of human volunteers to sulfate aerosols. Health effects and aerosol characterization.We found little or no evidence of adverse health effects from 2-hour multiple-day exposures to any of the compounds at "worst case" ambient concentrations. That's why I asked if you knew studies with empirical evidence, since a lot of mainstream assertions might be true or not. By the way, I find strange that in 3 decades of having those in the air in toxic levels, we didnt hear catastrophic annoucements from the media about it.  
> **username_0**: And.. https://www.nature.com/articles/d41586-018-07533-4  
> **username_4**: @username_0: There was quite a lot in the media in the 1970s and 1980 about the effects of sulfate emissions.  It's just that it wasn't primarily a matter of direct human health, but of the effects on lakes & forests: https://en.wikipedia.org/wiki/Acid_rain#History  

---

