The overall US population replacement rate has been on a downward slide for some time, and according to the US Center for Disease Control now stands at 1.7, which is obviously below what is needed for replacement; 2018 showed the lowest birth rate in the United States in over three decades.

Related coverage Bonds Building Bonds — Honoring Generations of Sound Investment JNS.org - If anyone in your family celebrated a bar or bat mitzvah, a wedding, or the birth of a...

Replacement is important for family and religious reasons, but also for economic reasons, particularly for the nation as a whole, if for no other reason than to provide a tax base to support an aging population. Also, according to a recent March of Dimes study, last year 43 percent of new births in the United States were to mothers receiving Medicaid assistance, many of whom are single mothers. Barring a dramatic change in birth rates or immigration, the overall US population in 20 years will be smaller and potentially poorer.

There are an estimated 5.7 million Jews living in the United States, the majority of whom are in the non-Orthodox movements. The replacement rate for non-Orthodox Jews is estimated to be even lower than that of the general US population, and the intermarriage rate has been measured to be as low as 44 percent and as high as 72 percent (with only a small percentage of intermarried families observing Jewish traditions).

Nevertheless, the birth rate among the US Orthodox population is more than four children per couple. A recent Pew study notes that the Orthodox population is also much younger. In the older Jewish generation, only five percent are Orthodox. In the current “parent” generation, 15 percent are Orthodox, and in the “child” generation, 27 percent are being raised in Orthodox homes.

If trends continue, the overall number of Jews in the United States will decline over the next two decades, and then begin to rise in the following decades due to higher birth rates among the more observant families. In perhaps 50 years, if trends continue, the United States will be home to the same number of Jews as today, but those Jews will be more observant and congregated in larger communities.

In Israel, the Ettinger Report recently showed the Jewish population hovering around seven million. According to the latest report from Israel’s Central Bureau of Statistics, Jewish Israeli birth rates are increasing, particularly in the both Sephardi and Ashkenazi non-observant, traditional, and religious sectors. (The birth rate in the haredi sector is actually decreasing, but still at 6.7 per couple.) Overall Jewish replacement rates are at 3.1 and climbing.

Today, 50.1 percent of Israel is Sephardic. In 20 years, through intermarriage, the distinction between Sephardim and Ashkenazim will be more difficult to determine and track.

In addition, the Jewish Agency for Israel reported that almost 30,000 Jews from across the globe made aliyah to Israel last year, up five percent from the previous year. While many of those returning are Jews were from Russia, Ukraine, and France, Jews have been returning from over 100 countries, speaking 80 different languages.

According to the Ettinger Report, with the inclusion of Judea and Samaria, Arabs would comprise one third of the total Israeli population, but the report also noted significant out-migration and a declining Arab-sector birth rate (although the birth rate is still around three children per couple). The report notes significant issues with over-counting and double-counting in the Arab sector.

The challenge with any type of population prediction, however, is accounting for the impact of individuals. A study of the Jewish population in 1875 would have shown 10 million Jews worldwide, the majority, perhaps three-quarters, in eastern Europe and Russia, and the rest around the Middle East and Persia. Projected Jewish growth would have been predicted for those two regions alone, based on birthrates at that time.

Who would have predicted the impact of Lenin or Stalin, or the rise of Hitler? Conversely, who would have predicted the impact of a newspaper reporter named Theodor Herzl?

Did anyone in 1950 predict the impact of the Lubavitcher Rebbe, Rabbi Menachem Mendel Schneerson, and other major rabbinic outreach efforts in bringing unaffiliated Jews back into the fold? (In Israel alone, there are an estimated 300,000 Jews who have returned to some form of Jewish observance.)

Did anyone foresee the return of millions of Jews from Arab lands to Israel?

How about the rise of the ayatollahs in Iran and the exodus of Persian Jews, many of whom trace their roots to the time of Mordecai and Esther? Did anyone foresee a Hollywood actor becoming a US president and successfully challenging the Soviet Communist empire, which ultimately brought some one million Russian Jews back to Israel? Who could have predicted the impact of Pastor John Hagee in America, and his inspiration to millions of Christians across the world to support Israel and Jews returning to Israel?

How Heavenly forces are interacting with these efforts to steer our people back to Israel is unclear, but that these and many other individuals have altered the Jewish demographic path is clear.

In 20 years, projections based on current population growth rates show the Jewish population in Israel approaching nine million, and in the United States dropping below five million. Will government and spiritual leaders impact the overall US population replacement rate? Will antisemitic leaders in the United States, Canada, and England cause aliyah to Israel to increase significantly from these traditional safe havens? Will sympathetic US leaders, organizations, and the forces they inspire continue to protect Jews and continue to be effective in supporting Israel?

No one can predict how the next two decades will unfold for America, Israel, and the Jewish people, but the continuation of the “ingathering” in the Promised Land seems likely to continue unabated. We can only hope and pray that this ingathering will unfold as peacefully as possible.

Gary Schiff is a US-Israel natural resource consultant based in Jerusalem and a contributor to JNS.