Weather in the Northern Hemisphere, Immigration and the Civil War

Source: 19th Century U.S. Immigration Statistics

I recently posted a thought on the possible effect of climate and weather in creating conditions leading to the Civil War. The graph posted there indicated that the period from 1810 to 1860 was "a little ice age" in the northern hemisphere. The figure above shows that immigration to the United States grew greatly during that period. It would seem likely that one of the driving forces for that immigration was the poor agricultural performance in Europe during the cold weather (and the potato blight that hit in the 1840s, which may also have been worsened by the cold weather).

Might the climate change have contributed to the pressures helping to cause the Civil War by promoting this immigration? The immigrants went primarily to the northern states and the immigrants may have been a source of cheep labor in competition with slave labor. (Indeed, I have read that Irish immigrants were used in especially dangerous occupations in the south because the financial risk was less employing a poor immigrant than a slave!) The immigrants also were very concerned with the maintenance of the Union. And of course, the immigrants were an important source of the soldiers who fought the war.