<a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Climate_engineering#Solar_radiation_management" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Climate_engineering#Solar_radi...</a><p>A full nuclear exchange is predicted to lower the temperature by about 20 °C. That depends on 7 billion tons of dust.